Is Naomi Klein a libertarian socialist?

Yes ,  her advocacy for : "“decentralising power and building community-based decision-making potential — whether through unions, neighbourhoods, farms, villages, anarchist collectives or aboriginal self government.”(Naomi Klein) is very close to the ideals of Libertarian socialism.

Yes she is, although “liberal socialist” might be more accurate as she has tended toward more reformist rather than radical approaches in the past.