LOL He’s training you to pet him and NEVER STOP. Except perhaps to get up to feed him but you’d better hurry back with that food.
Seriously, his licking is kissing you. He is very happy you pet him. Yes, flattening can mean “I’m ready for you to groom/pet me now.” also a good sign.
The digging and nipping means he wants more, but also that he is playing and exploring you and just doing bunny stuff.
He needs to learn to stop before nipping, so you need to communicate in bunny language. A loud sound is not as effective as you making a high pitched squeal. That is the noise a bunny in pain makes. Just squeak and he will stop.
You can’t punish a bunny. Ignoring a bunny is the most effective behavior for a negative response, and positive reinforcement of good behavior works extremely well too. So, if he is digging too much, or nipping, then playtime is over and he gets removed from your friendly lap. You just ignore him and go about your business. He will learn that if he comes back to you gently, maybe with kisses, that will get him pets again.
Also, if you are on the floor, turn your back on him if you’re both sitting. A bunny will turn away if he is displeased with you. A bunny fully turned is called giving you the Bunny Butt. That means “I am done with you” in bunny sign language. You do it to them, it drives them nuts. If you peak over your shoulder, it confirms that you definitely have given the butt and are checking to make sure he saw it. That’s what they do to us.