Which is a major cause of conflict and discord with present-day Russia?

Chechen nationalists seek independence

Explanation:

While it may be believed that Chechnya is a separate country outside the Soviet Union. Present-day Russians believed that Chechnya is still under their control and they must always bow to whatever decisions the Russia made.

The Chenchen nationalists however kept agitating for their independence from the hand of Russia

Hence, the major cause of conflict and discord with present-day Russia is that "Chechen nationalists seek independence"

the right answer is the constitution