Nikola was part of the Buća noble family of Kotor, in the Serbian Kingdom. The first known Buća was Tripe Mihov. Kotoran families held high offices in the Serbian court, and the most notable was the Buča family, while the most notable individual was Nikola Buća. His brother was Mihajlo Buća, also a diplomat of Stephen Dušan, and his nephew was Trifun Mihajlov Buća. Nikola and Toma Pavlov, another notable Kotoran, traded in salt. Nikola Buća along with Metropolitan of Prizren Arsenije, kaznac Baldovin, vojvoda Gradislav, župan Vratko, knez Grgur Kurjaković, stavilac Miloš, vojvoda Dejan Manjak, Gradislav Sušenica, and more, signed the letter issued by Stephen Uroš III, dated 22 January 1325, for the sale of some maritime possessions to the Republic of Ragusa. The possessions were Ston and Pelješac, which the Ragusans earlier had tried to buy through talks with Tripe Mihov. On 15 July 1326, King Stephen Uroš III confirmed that Andrija Peštić, Nikola Buća and Grubeta had paid their bills for some royal markets which they had leased. Buća had paid several people to gain control of business in Kotor; On 1 December 1326, he entrusted Ilija, the nephew of Bratoslav Dusinj of Ragusa, with 700 perpers, and then he personally invested in goods of Kotor which he sold in Serbia. In January 1336, Nikola and his brother Mihajlo became Ragusan citizens, and received the notable right of counselor. Their sons also received Ragusan citizenship. The granting of citizenship was a result of Buća's involvement in the sale. The most notable nobles of King Stephen Dušan received up to 1000 ducats, and Nikola Buća was given a plot of land in Ragusa itself, and a part of Ston. The city of Ragusa had highly enriched itself during the rule of Emperor Stephen Dušan, who had constantly granted it gifts and delegations. There are sources saying that the Kotoran nobles received fame during the reign of King Stephen Uroš III, when they, under the command of Nikola Buća, captured the Bulgarian flag and cross during the Battle of Velbužd. He probably had supported Dušan's overthrow of his father, King Uroš III, in 1331. In 1344, he asked permission to build the Dominican Monastery of St. Nicholas in Kotor. Buća held the title komornik, prior to the crowning of Stephen Dušan as Emperor, at which time the Serbian nobility and clergy were elevated in titles - Buća was elevated to protovestijar. The protovestijar was the chief financial official. Buća had a number of associates and business partners in his near relatives. The power of the protovestijar is best testified by the proverb: "Car da – al Buća ne da". Buća accompanied Emperor Dušan on his visits to Dubrovnik and Kotor, in 1350. He died in 1354. His nephew Trifun Mihajlov Buća, one of the most known and important persons in his time, served Emperor Dušan's successor Uroš V as protovestijar.
Family
Nikola Buća married Dobra Gučetić, sister of Klement. They had following issue:
daughter, Bijela, married to Maro Goca.
daughter, Bika, married Marin Gučetić in 1349, in exchange for 1000 ducats, 100 aksađa gold and other equipment.
