It depends, my own Betta has stopped making a bubble nest because my filter is a bit too strong and agitates the surface a bit much for his tastes. If you can, reduce the output of your filter and he'll probably buble nest away if he hasn't already.
All a bubble nest means that he's ready to mate. So don't worry if he doesn't make one as it's not a symbol that he's perfectly happy and healthy. They can and do make bubble nests while dieing in those horrible little bowls and vases.