Nothing (in) particular

I think "nothing particular" looks more natural in both these contexts. In my opinion "in particular" is used to mention some thing as a better example of a condition, situation, event etc.

Hello. Let me ask you one question.

Which sentence do you think is more natural?

1. Are you busy now?
No, nothing particular. No, nothing in particular.

2. What do you do in your free timea?
Nothing particular. Nothing in particular.

Thanks in advance.

I've never heard "nothing particular."

As written, the first sentence is a "yes or no" question. It would be "more natural" using the word "doing":
What are you doing? Nothing in particular.

Then, sentence 2:
What do you do in your spare time?
Nothing in particular.

Of course, the younger generation would answer "hanging out."