It's nice to be nice, but super nice? That makes my teeth ache. Super nice people are so nice that it's hard to be comfortable around them. Then you have to ask yourself what "nice" really means. She's a nice girl. (Plain but pleasant.) He's a nice guy. (Friendly but ineffectual.) Perhaps a better ambition would be to be thoughtful, or friendly, or supportive. Whatever you call it, just remember that the most important person in your life is YOU. If you look after yourself without trying to take advantage of other people, that's nice enough.
As long as you are not just being nice to be nice, you're ok. That is just as bad as being mean to be mean. If your goal is to be liked by everyone, you will be just as unsuccessful as those who strive to be hated by everyone are successful. People in the helping professions (doctors, counselors, teachers,etc.) have this idea called "unconditional positive regard" that I try to live by. Basically, you assume everyone you meet is as good and decent a person as anyone else until they give you reason to believe otherwise. Usually I find that if I approach each person I meet in such a countenance, I am proven right. And if I am not, I know it was them and not me, and the gloves come off.