Let me start by saying I have limited knowledge of youth tournaments.
However, based on my understanding...
It really depends on the tournament and rule set.
The thing I believe you are looking for is whether each tournament allows for a:
Neck crank WITHOUT choke.
This was illegal in a few adult tournaments I have even participated in, because it's considered to not be a choke but rather a pure neck crank. Notice how he is cranking his neck but the arm isn't cutting off blood or air to the right side of his opponent, unlike an arm triangle.
Some tournaments will still allow this, especially if they favor grappling vs pure jiu jitsu.
Many will not allow this.
Hopefully someone with a bit more experience with the youth levels can give a more definitive answer, too.