To you, your baby is the most adorable thing in the world. They have a name, but you have a thousand nicknames for them. Most of them are nicknames you probably wouldn't use if your friends or family could see you, but if it's just you and the baby, there's no harm done. Except, of course, when there is.
At some point, you're going to want your baby to learn their own name. They can only do that if you consistently use it when you're referring to them. If you want a baby to take information on board, you have to make sure you're giving them that information clearly, consistently and repeatedly. Otherwise, you're running the risk of your child going to nursery and introducing themselves to people as 'Mr. Snuggle Pants', which is something both they and you may find yourselves explaining to a therapist one day.