In 1272, he is referred to as her vice-chancellor, but it is possible that he already held the office under the direction of chancellor Philip, Bishop of Vác in the queenly court since 1270, when Stephen V ascended the Hungarian throne. When the minor Ladislaus IV was crowned king in Székesfehérvár around September 1272. In theory, the 10-year-old Ladislaus ruled under his mother's regency, but in fact, baronial parties administered the kingdom. As a supporter of queen dowager Elizabeth, Nicholas Kán became vice-chancellor of the royal court, held the position until February 1273. Meanwhile, the episcopal see of Esztergom remained vacant after the death of Archbishop Philip Türje in late 1272. Elizabeth was trying to achieve the election of her protege with all the means. When the cathedral chapter of Esztergom convened between 12 February and 1 March, Nicholas Kán's army surrounded the building, locked the canons and deprived them of food and water with the tacit consent of Elizabeth. Under such conditions, the intimidated canons elected Nicholas as Archbishop of Esztergom. Additionally, he also became royal chancellor and "ispán" (count) of Pilis County for a short time in May 1273, when Queen Elizabeth temporarily regained her lost influence over the royal council due to the Bohemian invasion. However Pope Gregory X and most of the later liberated canons refused to acknowledge the validity and legality of his election. When the Kőszegi family and their allies deprived Elizabeth and his courtiers from the power in June 1273, they declared the episcopal see as "sede vacante" again. As Elizabeth never regained her central position and decayed into nominal regency, Nicholas Kán lost his political influence for years. The canons of Esztergom elected Benedict as the new archbishop in February 1274, who held the dignity until his death in November 1276. Nicholas arbitrarily adopted the title of archbishop and vice-chancellor already in December 1276. However, some canons nominated Peter Kőszegi, an influential member of the rival baronial group to the position in March 1277. Pope John XXI summoned Nicholas to Rome per Lodomer, Bishop of Várad (today Oradea, Romania) the same month, but Nicholas refused to attend. Pope John died on 20 May 1277, and Pope Nicholas III succeeded him after a six-month vacancy.