There is a ''breaking'' point when the NBA dudes reach a certain amount of being comfortable on skates they would likely be able to win quite easily, even if they skate real bad and real slow. I mean while the 11 years olds obviously skate better, shoot and pass, we are talking about 7-foot high-end athletes here. As soon as they are comfortable on the ice they will easily be able to stop these kids in their tracks and advance towards the other goal by protecting the puck with their giant body.
Just two NBA dmen + an NBA goalie standing around the goal not even moving would likely be enough to stop most scoring chances from the 11 years olds. Then get 3 guys who can somewhat skate at forward and they could score a bunch of goals for the NBA.
Obviously, if none of them can skate, the kids will win.