I have a similar setup with a fire tv going hdmi to tv and optical to the peachtree. I also have the computer on a separate hdmi to the tv for video and USB to the peachtree for audio.
After using the Nova150 for about a week and a half, I'm finding my favorite connection for digital music is from my MacBook Pro via USB to the amp. Unless I'm missing something, this USB connection seems to offer several advantages over Airplay streaming from a Mac or iOS device:
1. iTunes on the wired Mac allows multi-casting to Airplay targets. As far as I can tell, from the iOS device one can choose only 1 remote Airplay target at a time (e.g. iPhone to bedroom AppleTV or to family room Airport Express, but not to both at once)
2. iTunes on a Mac supports ad-free internet radio playlists. These are not exposed to the iCloud Music Library via iTunes Match. To get internet radio stations on Apple TV or an iOS device, apparently one needs to install 3rd party apps like TuneIn (and pay subscription fees to get ad-free content). The selection of 3rd party radio apps seems to be rather limited for tvOS.
3. iTunes on a Mac offers better volume control, IMO, than the little sliders available in the swipe-up iOS control center. By pressing and holding the USB-B source selection button on the Nova150's front panel (until it turns from blue to green), I can transfer volume control to the wired source device (my Mac). Then I can control volume easily, fully and precisely from the keyboard F10-F12 keys. I also can control L/R balance via Audio Midi setup.
Once the USB connection to the Nova is in place, play can be controlled from the Remote app on an iOS device, or via VNC from another Mac. I like the AppleTV's user interface, but find the Remote app's UI is nearly as user-friendly (although it does use those little touch screen sliders for volume control, which I don't like as well as physical buttons on a remote control or keyboard.)