Nissan rogue 2013 code P0420?

I’m still learning but please educate me more about this code please
So my car (Nissan rogue 2013) been having problems with overheating lately, but only if it’s sitting while the engine is running. I’ll turn on the heat so the hot air will escape from the engine.
And the oil hasn’t been changed in a long time. It’s been over 15000 miles since the last change. I know, I’ve made a mistake by neglecting it.

Well today, as I was making 2-3 turns coming onto the interstate, my oil light has came on and off. Just only when I turn.
Then afterwards my check engine light came on. Car didn’t overheat as I was driving.

So my question is, does p0420 have anything to do with not changing the oil? I’ve checked it and it was dark brown and very little. I am getting it changed though today.

But if it doesn’t have anything to do with the oil,
Could it be coolant levels? I’ve checked that too and it was very hard to tell.
Please explain this to me in crayon eating terms lol please and thankyou🙏
Nissan rogue 2013 code P0420?
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