If this is the only action running on your node, you can check this using:
if (!lionNode.hasActions) { // check if no actions are running on this node
// action code here
}
Alternatively, you can set your boolean in a completion block that gets called after the action runs and completes:
[lionNode runAction:[SKAction sequence: @[lionJumpActionUp, lionJumpActionFly, lionJumpActionDown, lionJumpActionPause]] completion:^{
BOOL isActionCompleted = YES;
}];