I believe the word does exist as teenage slang, meaning a shortened version of naturally, however, I have never heard anyone use it.

Here's the question that you wanted to ask: 'Does the word "natch" exist in English?' We use the present simple for talking about facts. When we make a question in this tense, we usually need "Do" or "Does" before the subject. Check your grammar book. And the answer? As a couple of others have said, it's slang for "naturally", meaning "of course". But as with most slang, it is (or was) used by a limited group of people for a limited time. I wouldn't say it, and nor should you.

Natch! :D Yes, it's a slang abbreviation for "naturally". However, as with most slang, I think this expression is very much outdated. Who knows - it could come back into fashion. ;)

I've never heard this word being said in England.

nach,means after. Nacht,means night.Both are German words.