That fork costs, and is worth more than any Next bike. You could, and I as well as others here would reccomend you look at new bikes first.
I am glad to see you are riding, but as the saying goes friends don't let friends ride junk.
Some call it God's country. I call it Acton, Maine
Too Many - 7 or 8
The simple answer is, yes, you can. But as Hunter indicates, why? Next bikes are 1 of 2 brands I will on occaision, refuse to work on. The minimal quality level is hit or miss with them.
That said, it sounds like you are at least working in the right direction. Historically, their weakest link has been the OEM(Original Equipment/Manufacturer) forks they come with. And RST forks are solid.