My question is how to print NodeMCU local IP on my Nextion display.
While the question is simple enough the lack of information about what you are using, what you have tried and what results you got are not at all helpful.
I would think that in the unspecified Wi-Fi library there will be a function that returns the IP address (It's an IP address, not an IP).
I'm going to assume you already know how to display a variable on a Nextion display by printing it to a text box, so you just call the function to get the IP address then print it to a text box the same as you would any other variable.