Lepus Rex,

When the USSR broke up and independence was claimed by the former Soviet Socialist Republics, Chechnya and other areas of the former Soviet Union were not among them. One reason for this was because they would have been totally unviable as "states".

At the end of the First World War when the Austro-Hungarian Empire was dismembered a number of "states" were created that were unviable. In order to make them viable various parts of Germany were broken off, complete with their German populations (who were never consulted on the matter), so that these new states would have some form of industrial capability, some form of natural resources, a corridor to provide access to the sea, etc, etc. Disaffection with this arrangement was one of the root causes of what became known as the Second World War.

So what would make the State of Chechnya viable - various lumps of real estate round about them - so how do they get hold of those - either by force or by persuasion - from what I can see the Chechens have little or nothing to offer so persuasion would be difficult. Perhaps their former rulers could be convinced to continue to support them - sort of like a big theme park.

Maybe large tracts of present day Poland and the Sudatenland should campaign for re-unification with Germany - it would make EU enlargement a bit simpler.

You ask:

"What more should a nation have to be recognised as independent?"
Simple it should have means to survive and thrive as an independent state.