His political career began in 1977 as an employee of the SovietEmbassy in the GDR . From 1982 to 1986 he was third and then second secretary of the USSR Consulate General in Erdenet , Mongolia . In 1988 he completed courses at the Diplomatic Academy of the Ministry of Foreign Affairs of the USSR and was appointed in 1992 as First Secretary and Advisor to the Russian Embassy in Germany. In 1996 he took over the management of the German section of the Fourth European Department in the Russian Foreign Ministry, From 1999 Nechaev worked as a chief adviser to the Russian Embassy in Germany.

From 2001 to 2003, he served as Russian Consul General in Bonn and then served as Deputy Director in the Department of Foreign Affairs’ Fourth European Division. In 2004 he moved to the Third European Department of the Ministry of Foreign Affairs as deputy director and in 2007 took over the management. From 9 March 2010 to 10 August 2015, he served as Ambassador Extraordinary and Plenipotentiary to the Russian Federation in Austria , later re-chairing the Third European Department of the Ministry of Foreign Affairs. On January 10, 2018, he was appointed as Extraordinary and Plenipotentiary Ambassador of the Russian Federation in Germany by Decree No. 9 of the Russian President .