Played in the 32nd Chess Olympiad (1996), in the Zonal Tournament in Panormo (1998), when he came =7th and narrowly failed to qualify for the FIDE World Chess Championship of 1999. In 2000, he played in the 1st European Individual Chess Championship. He came =7th in Armenian Chess Championship of 1999.

Other results include: =1st at Czestochowa 1992; 1st at Tbilisi 1996; =1st at Pasanauri 1997; =4th at New York 1998; =2nd at Moscow 2004; =6th at Kuala Lumpur 2006; =2nd at Tarakan 2008; =3rd at Kuala Lumpur 2008; =6th at Seoul 2008.

In 1998, Nadanian was awarded the title of Honoured Coach of Armenia and in 2007 FIDE Trainer. He is the former coach of the Kuwait National Team (1999–2001). Currently, he is the National coach of Singapore Men's Team (since 2005). His students include Grandmasters Gabriel Sargissian, Varuzhan Akobian and Davit G. Petrosian.

He has made a number of contributions to opening theory, the most notable of which is the <Nadanian Variation of the Grunfeld Defence <1.d4 Nf6 2.c4 g6 3.Nc3 d5 4.cxd5 Nxd5 5.Na4>>.

Author Tibor Karolyi devoted a chapter of his 2009 book Genius in the Background to Nadanian, calling him "Kasparov's Half-Brother"

Here is an article, <The Soul of the Budapest Gambit> written by Ashot Nadanian:

"In 1998 I was playing in the Linares Open tournament. One day I bought some food and among other things there was some canned fish. In the evening, a very young Levon Aronian entered my room. He picked up the tin, and seeing the logo of the manufacturer - a tiny kitten - he asserted - with healthy laughter - that it was food for cats. Although he knew that it was not so, Levon nevertheless made fun of me during the whole tournament. 'Well, have you eaten Whiskas today?' Or: 'The store still has food for cats?' His laughter was contagious and made me laugh along. Six years later my daughter was born. One day I met Levon. 'Congratulations, Ashot! How did you name your little girl?' 'Her name is Kiti.' 'See? I told you it was Whiskas!'"