Capitalism and imperialism are essentially the same thing, lack of opportunity for imperialist projects is in no way evidence of opposition to imperialism. If you believe the elites in Russia have any ideological objections to imperialism then I have a bridge to sell you.
Nationalism (like all populist ideologies) exists purely as a means of controlling the masses, the oligarchs who control every capitalist state are interested only in how much money/power they are personally able to amass.