This is where you get into the weird and wonderful world of frame geometry. If you calculate the stack and reach for the two bikes, the Outlaw in 52 actually has a longer reach than the Nova Sport in 54 (384mm vs 375mm). The Outlaw also has a much lower stack (527 vs 557). So assuming you put the saddle in the same position relative to the BB on both bikes and all other things being equal, your hands will be ~1 cm farther away and ~3 cm lower than on your current bike. Note that I'm guesstimating the Nova fork length (I've measured the Moto CX fork), so if it's actually shorter that would reduce the stack difference. But, in general, the Outlaw is a more "aggressive" geometry which might actually make it feel bigger than your current bike.
If you look at how Jamis sizes the Nova, they're using "effective seat tube". The "54" is actually only 51 cm BB center to top of TT. Motobecane sizes the Fantom line by actual seat tube length BB center to top of TT. That means the Outlaw actually has a longer seat tube than your Nova. Of course you can always go ride it and see for yourself, but if you're trying to size down (or the other guy is trying to size up) it's probably not a worthwhile trade.