I think this prize recognizes her courage and fight for human rights.
Dismissing that as "just being in the opposition" ignores the reality of what it takes to stand up to Maduro's dictatorship.
A dictatorship can be peaceful, and a democracy can be warlike. Venezuela hasn't been involved in any war recently as far as I know. Of course people who fight for democracy deserve being praised and supported, but to me it looks odd to do so with a peace prize.
The prize is supposed to be awarded to people who have "done the most or the best work for fraternity between nations, for the abolition or reduction of standing armies and for the holding and promotion of peace congresses". Is this the case here?
While the point you're trying to make may or may not be valid, Venezuela is not a good example. Go read up on the Venezuela-Guyana crisis. The Maduro regime has been pushing the region closer to war in recent years. Renewing its claims to Guyanan territory, and preparing its military for war. For now, all out invasion has been prevented partially by significant support for Guyana and pressure against Venezuela from neighbouring countries and the west, and distraction from its own internal problems.