Question

is bad right as an opposite of nice

Answer 1

Bad is right as an opposite for nice.

A few more antonyms you could use could be:
Aloof
Disagreeable
Unpleasant 
Horrible
Nasty, etc. 

Answer 2

Bad is right as an opposite / antonym of nice, because when a person is nice to you, he is considered to be kind and honest to you. But, a person is said to be bad when he is rude and dishonest, not to mention cruel to you. That's why everyone unconcerned of the other person's behavior, should always be nice.