What Is Their Difference?
One of the differences between 'nothing' and 'anything' is that the former is a negative making indefinite pronoun and the former is not. Let's discuss them!
Nothing vs. Not Anything
Let's consider these two sentences:
As you can see, one of the sentences has an affirmative verb and one a negative verb.
Notice that, 'nothing' as a pronoun is in the negative form, so the verb must be in the affirmative form. Otherwise, there'll be a case of double negative which is a big mistake in standard English.
When we want to refer to the absence of a thing, the common construction is 'not ... anything'.
The verb is then in the negative form because otherwise, we have a case of a double negative.
When you need to build a sentence using a negative pronoun at the beginning of a clause, you then have to use: NOTHING. Therefore, the emphasis will be on the negative form.
In conclusion, the difference between sentences like:
is that the first sentence can be used more emphatically. It puts emphasis on the absolute absence of a thing. It actually sounds stronger for most people. It begins with an affirmative "I have" and then proceeds to the absolute "nothing".