Nevermind the spelling

So this one is kind of a shower thought.

I was thinking about the fact that the never mind as word is written in two words. But people seem to spell it more often in one word. Just like it was spelled by Nirvana.

So my question is, could it be that Nirvana changed the way we write one of the most common word in the english language? After digging around about it on the internet is seems like there are multiple people are wondering the same thing. Anyhow, Would love to hear you guys thoughts on it.