WTB Nano Raptor tires, yay or nay?

I love me some Nanos! Very fast and smooth rolling tire, and the tread lasts a long time even if you mix in some pavement use. As noted they don't have much of anything in the cornering knob department so don't push your front end too fast through a turn or it might slip out (though the Nano does at least slip predictably and smoothly giving some chance to recover).

Even if you want a bit more confidence and capability out of your tire setup, I wouldn't fret over the bike coming with Nanos because in my experience they shine best as rear tires and you can always use the stock front Nano as a spare for the rear. The fast rolling of the Nano and it's long wear life is exactly what I like in a rear tire, and the volume is decent for a 2.1. The lack of cornering bite doesn't really matter too much in the rear because of the different forces at play on the rear wheel while cornering. Mine have slid out in back only a couple times ever. A 2.1" 29er tire like this feels less harsh than a 2.1" 26" tire too. I've been pretty happy pairing a rear Nano with front tires such as the Maxxis Ardent, Specialized Purgatory, WTB Weirwolf and Panaracer Rampage, and it's always felt like a fairly balanced setup on the trail unless I'm going for lots of air or hitting big rocky sections hard where any 2.1 just won't have enough volume to feel good.

Also, not sure if this applies to what you'll be doing, but Nano's at higher pressure fly on roads and paths. They're as close as you'll get to a proper commuter road tire from a tire designed for mtb use.