What is your nation's leader's title?

[Malfyria]

His Glory the Vitreous and Terrible Emperor of Malfyria and her Dominion, purest of blood and mind, guardian of the people,mighty conqueror of empires and Benevolent father of the
Malfyr.

[New Lyrane]

Utenene.

It would not be incorrect to call the head of state of New Lyrane 'President' in galactic terminology, because that is what she is. But her formal title is simply Utenene. It means literally 'elder sibling of shared parentage'.

[Mkuki]

"The title of Mkuki's head of state is the General Secretary. The head of the Government is formally titled the Commissar."

~ Colette Herzen, Chief Assistant to General Secretary André Martel

[Everia]

The Autarch.

[Udema]

Hänen Majesteettinsa / Her Majesty:
Tove, Jumalan armosta Udeman kuningatar, Udeman oikea rouva ja isäntä
Tove, by the Grace of God Queen of Udema, the true Lady and Master of Udema

The Prime Minister is simply the Prime Minister (in Udemaner: pääministeri).

Sincerely yours,
Bianca Woolley
Private Secretary to HM the Queen

[Rodrania]

Your nation's name is Redrania and mine is Rodrania... lulz I love when things like this happen and you find your almost exact clone on NS

[Folik]

President of Folik.

[Meridiani Planum]

Prime Mover.

[Hydron]

Colonial Governor of the sauritican colony of Hydron

[Aleckandor]

Shorthand: Confederate Caesar 'Rohptor Wehndyg'

Official Version: Supreme Military Overseer, Chief Policy-Maker, & Executive Confederate Caesar 'Rophtor Fymahna Wehndyg'

[Ygganda]

Lawgiver to Ygganda

[Imeriata]

His royal Highness Oskar rex stjänkhrone II by the grace of the gods high king of the absolute royal federation and divinely appointed ruler and unifier of the Scandinavian races, the descendant of the first Imerian high kings especially and foremost Emanuel the first, Son of Primus the XIIIth, the son of Emanuel the VIIth, the son of Gustav the IInd, the son of Anders the IIId, the son of Emanuel the VI, the carrier of the royal sword first carried by the demigod Belrion son of Bel, vanquisher of evil, Tamer of the mighty dragon Katla, Slayer of the dragon Harimir, Gardark and Salram, the defender of all inferior species and destined ruler of man, Champion of life and light, defender of the living and vanquisher of the dead, the protector of the federal crown jewels, the holder of the sword of Halmir and carrier of the enlightened torch of civilisation, vanquisher of communism, socialism, syndicalism and national socialism, The grand defender of monarchy and patriarch of the noble house auf stjänkhrone, carrier of better and more important titles than the space Russians, Chief of Chiefs, Shan of Shans, as well as the protector of the free city states of al-Jzr al-Khḑrā as well as defender of Hungary and her regions and the realms as king of Imeriata and as such the defender and autocrat of Söderlandet, Norderlandet, Aster öarna, Vast öarna, Sydvedian, Storfloden and the river king, king of Vedian and the duke protector of Ostmark, Millanmark and Vastermark, king of Erathia and as that the duke of Ankea metsä and ruler of the thousand lakes, the lord and defender of lännenfilmi ajaa vapaalla and pohjoinen kallio, over the ancient rivers river, from the ancient mountains mountain king of Karmanjaka, king of Northern Taranakan, king of Chanjing, and king of Andervel but also the righteous and lawful king of New felandia and the king emperor of Dajing, the duke of Sydvinland, Northern Venezue, Sthalinge, Gustavsland and Sjöland, The Shah of the crown states of al-Jzr al-Khḑrā and the Padishah of all of al-Jzr al-Khḑrā, The lord regent of the colony of Nova Imeriata, Imerian Africa, Angland, the two peninsulas of Tvaude and of Somalmark, The Grand duke of Suderland, The prince of Isarna, Salmo, judeheim and Khan of Salonia, Tsar of Nordomark, Sultan king of Ramir, the Emir of Sandland and Jarl of Salywa and the free city of Krakborg and Styrfastning, defender and lord of the city of Arkham and Sirmera, and further more the ruler of the federal terretories of Vastermark and the northern iceplains, By the right of the constitution of the protectorate leopridaeria prince defender of leopridaeria, the high lord of Kalmer, Salmoborg and Gaseborg, Lord of the countless cities and lands under his most blessed and righteous rule, the lord defender of Imerbürg, Coparborg, Vesiki, Sjöborg, Afrikas fastning, Erikasborg, Nova Imerbürg, Wein, Udeborg, Angborg, Ambir, Nya Landborg, Nymarksborg, Sorgerstad, Anderborg, Nordanstad, Kängruborg, Sthalstad, Kängruborg, Judeborg, Moskstad, Daji, Sajing, Ademarksborg, Salem, Söderhamn, Öborga, Dragograd, Gapur, Bor-zut and Táibĕi but as well the Enlightened Emperor of Nicksyllvania and as such the King of Leazus, Emperor of Helman, Grand Prince of Zeth, Emperor of Japan, Emperor of Jungria, Duke and king of Hornet-Kereburos, Despot of the Great North, Grand Duke of the Western Badlands, Master of the Southern Marshes, and the king of Dragkon and the wielder of the Holy Swords, the Demon Sword Kaos, the Holy Sword Nikkou, and the Greatsword of the Empire, Nickiller, Great Protector of the Helman Wall and Majino Line, also by the right of his birth high marshal of the royal guard and the Imperial commander of the Imperial nicksyllvanian army, the grand commander of the federal order of the golden sword and the Nicksyllvanian order, the knight commander of the order of the golden cross and the order of Africa, the lord commander of the colonial order, the high commander of the federal order of the silver rose and the order of Scandera, the Taranakan order and the Order of Vinland may his reign last until the end of time and may the empire and federation he rules stand even through the flames of the endtimes to protect all of his royal highness subjects.

[Sakarnen]

There are several titles associated with the Emperor: His Majesty the Emperor-Wyld, Sovereign of the Twelve, Protector of the Dominions, Lord of the Evening and Morning, First of the Tower, Guardian of the River, Keeper of the Scepter, Slayer of Heart and Soul, Creator of the Greatest Punishment, He Who Is Owned Only By The Land; only the first is used outside of ceremonies, announcements, declarations and such nowadays.
For an Empress, the titles would of course use the female forms where applicable.

[Mittens Romney]

Meep Man

[Moronus]

His Imperial Majesty, the Right Honourable Lord Emperor Hensigne of Vinland, Lord Emperor of the Great Empire and Lordships of Moronus, by Consensus of the People, Vinland Premier, Commander of Moronesian Forces, Legislator General

[The United Federations]

Founding President Robert Venor

[Arstrotzka]

Chairman of the People

[InuYashastan]

President.

[Venetoria]

The Emperor of Venetoria, The Lion of Sythoros and Protector of the realm, His Imperial Majesty, Frederick Merovingian III.

[Rebelian States]

The People’s Minister Conrad Lorne Talon. However his other titles are: Chairman of the Council of Guidance, Eternal Defender of Civil Rights, and Executive General of Defense

[Tulija]

Arch Minister.

"The Eminent" or simply "The Right Honourable" as titles.

[Strange Islands]

Lord Christoffer Strange, Protector of All Strange Islands, Earl of Mountormond and Strange, 6th Lord of The Islands

[Devidia]

Chief Statesman [name]

[Texas and Oklahoma]

Head of State is President and Head of Govt. is Prime Minister.

[The Republic of Mattlandia]

The Benevolent Dictator.