Is it okay to punish my puppy?

I'm going to say yes and I'm saying this while I tiptoe walking on eggshells because I don't want to rub anybody the wrong way. Dogs need discipline no different than a child needs discipline, so yes. If I stuck with a short answer, I would simply say yes, but I feel like I have to explain.
If you catch them in the act of doing something undesirable, such as messing in your house, chewing on your favorite shoes, fighting with another animal, trying to bite you too hard, or anything like that, it requires correction in moderation. It doesn't mean you have to go smacking them around. A lot of times it's just a loud noise. And most dogs when they hear that and they stop, that's correcting in itself for probably 80% of puppies. Have I at times tapped mine on the nose if they're really not getting a message, if they're not responding to an auditory stimulus or something like that? Yes, I have. Is it okay? I think it is in moderation.
again I am not advocating going around smacking your dog. But they do need correction. They need discipline and they do better when they know what's expected of them exactly like a child would be. If caught in the act, yes. If you were trying to correct them for something that happened maybe while you were at work, it might've happened hours ago, nah, you're wasting your time. And I have learned the hard way, do not even bother because they will have no idea what you're correcting them for. And then it just becomes a thing where, oh my goodness, now they're fearful of you because you're just this big old guy that just comes in and starts spanking them for no known reason. So if you catch them in the act, yes, punish in moderation, otherwise let it go. Deal with it the next time you see that behavior happen.

I try not to use the word punish. I do like to say; we want to do positive reinforcement. And so, instead of negatively punishing them for something they did wrong because they are not going to retain that very well, I try to positively reinforce behaviors that I do like. So if the puppy is doing something that you want them to do, or even if it's in the direction of what you want them to do, you want to praise that, whether that be with treats or even just telling them, they’re a good boy or girl. You’ll get a nice little tail wag because that shows that they are just so excited that they did something that made you happy.