nagsock
A nagsock is a person who talks nonstop, like they have a never-ending monologue stuck in their head and won't let you live.
My dad is a nagsock. He talks about his golf game even when I'm trying to sleep.
My friend is a nagsock. She won't stop texting me about her cat's weird behavior.
My teacher is a nagsock. She keeps telling me to stop talking even when I'm not saying anything.