(Taken from Urban Dictionary)
Nya is simply japanese for meow, while also being fun to use in sentences at random.
Nya is a word they use in Tokyo Mew Mew. anda can use it when your happy atau sad. If anda get excited anda could say it. Some people say it instead of hello. Others use it a question. If something makes anda jump anda could say it as a reaction. Some say it out of habit.
(Wikipedia)
nya (hiragana にゃあ)
Onomatopoeia The sound a cat makes, meow.
So basically, Nya means Meow. What a cat says. So, now that anda know, please, dont ask anymore, Nya!
(Yes. I say Nya at school sometimes. School gets boring. Sometimes I try to make school lebih interesting!)