The standard scuba/snorkel mask will let you breathe out through your nose, but it won't let you breathe *in* through your nose because the nose pocket is sealed.
Are you a decent swimmer? Ever tried snorkeling? How did it go?
Here are a couple of things you can try cheaply and easily, to see if you can master the airway control you'll need:
Borrow or buy a snorkel and mask, and bring a friend to the pool to help out and supervise everything.
* Snorkel around the pool, wearing the mask and breathing through the snorkel. You should hold the snorkel mouthpiece gently with your teeth, not really with your lips.
* Standing with your face submerged, take a deep breath through the snorkel, remove the snorkel, put it back in, and blow air out hard to clear it. Then take a careful little breath in through the snorkel to make sure you get air instead of water. Clear the snorkel again if there's still a little water left in there. (Scuba regulators are actually easier to clear than a snorkel.)
* Standing with your face submerged, breathing through the snorkel, flood the mask a little by breaking the seal at the top, then hold the top of the mask onto your face and breathe out through your nose to clear the water out of your mask.
* If that's easy, flood the mask completely before clearing it with your nose.
If you can do those things, I would try a Discover Scuba class to see how it suits you. You'll need your doctor's permission to do a Discover Scuba with a disability. You can get the doctor's permission form from any dive shop or online. Discover Scuba will require you to be able to take your regulator out, find it, put it back in and clear it underwater. They will also require you to clear a flooded mask using your nose. The snorkel skills above are practically the same skills.
To get open water scuba certified, you'll also need to be able to do something similar to:
* Snorkel with no mask on at all (just hold the snorkel above water), or wear swim goggles instead of a mask so your nose is not covered. This is similar to the scuba mask-removal skills. You have to avoid breathing in through your nose to do this. It's easier for some than for others, but most people can get the hang of it.
* Remove the snorkel (regulator), replace it, and clear it several times while swimming.
If you can do all of those things with a snorkel, you should be just fine with the scuba airway control skills.