Welcome to the forum Kansas Kid, glad you joined us.
Don't think i have built a Nel Lusso but I did build a Panama jack years ago. I believe they are the same bike with the same size tires? I did not have any problem with chain and tire rub on the PJ.
Be sure to beef up your fender mounts if you plan to keep the fenders on. They are notorious for breaking...
I changed to a strong BMX chain that is thinner than the 415 standard kit chain to clear the rear tire. I use a Wippermann BMX 1R8 chain. It is 1/2 x 1/8 and is one of the strongest BMX chains available. It is nickel coated with reinforced plates. It has a breaking load of 12,500 Newton. It's thinner than the 415 and you can use it as a regular bike chain too, but I found that it runs through my china girl sprocket much smoother than the bulky 415. It will run through the standard 41 tooth wheel sprocket with no problems. Depending on the engine you ordered you might have to get a thinner 10 tooth engine sprocket, you can find them online for less than $10 if your engine doesn't come with one.