I agree with the other two members that 'Nothing malicious' isn't an expression that anyone uses. I also agree with Luna that 'Nothing personal' means 'I had (or I'm having) to do something mean to you, but it's not because I don't like you'. We say this usually just before, or just after, a potentially upsetting comment, in an effort to soften its effect. 'No hard feelings' is usually said following an argument or difficult conversation, as a means of parting from the other person on reasonably amicable terms. It can also be a question. You might ask 'No hard feelings?' to someone at the end of a conversation, just to check that they are not feeling resentful to you.

In my opinion, these do not have the same meaning. no hard feelings really means "I won't be mad at you and I hope you won't be either" nothing personal really means "I had to do something mean to you but not because I don't like you" nothing malicious, I agree, is not an expression that I have heard before and I don't think is used. hope that helps.

Not exactly. "No hard feelings" and "nothing personal" are similar, we use them to avoid resentment in some situations. "I'm sorry John, but you can't work here anymore. It's nothing personal." "I hope you're not mad that I beat you in the competition today Bob. No hard feelings." "Nothing malicious" isn't really an expression that is used. "Malice" is a stronger negative emotion than resentment; it implies a wish for something negative to happen or a feeling that there would be satisfaction if there was revenge.