It can be natural, especially if it refers to a whole dish involving noodles.
If you serve your friend a dish of noodles, for example, the conversation might go like this:
Mmm, this looks good. What is it?
It's noodles. ( or perhaps 'It's noodles cooked with garlic')
Here are three sentences, all in the singular. We're using 'noodles' to refer to the dish - referring to how you've cooked, seasoned, and served the noodles. Once the noodles have become a dish, they can be seen as a singular item.