One of the tenets of Nanowrimo and all stream of consciousness writing is just write. Let it flow. Don’t make corrections, just get it out. Edits are for December.
How I do this is if I have a word that I know I don’t want to use, but need it to get the thought across, I will add [th] after I type or write it (I do this regardless of long writing or typing) so I can search for all of my [th]s and then look the words up in a thesaurus. That way, I can keep the writing flowing and get it out, and that works for me. I also keep a list of words to look up, words I find in my travels, words that I want to use, and want to know more about their definitions.