Also happens with my machine, Antergos/Gnome/Wayland latest repo update (no
AUR) with AMD FX8350 and NVIDIA GK104 [GeForce GTX 760] (rev a1)

First crash I was watching YouTube, in journalctl I got this:

kernel: nouveau 0000:01:00.0: Xwayland[1012]: channel 13 killed!
kernel: nouveau 0000:01:00.0: fifo: engine 0: scheduled for recovery
kernel: nouveau 0000:01:00.0: fifo: runlist 0: scheduled for recovery
kernel: nouveau 0000:01:00.0: fifo: channel 13: killed
kernel: nouveau 0000:01:00.0: fifo: read fault at 000a5e0000 engine 00 [GR]
client 04 [GPC0/T1_1] reason 02 [PTE] on channel 13 [007ed50000 Xwayland[1012]]
kernel: nouveau 0000:01:00.0: gr: GPC0/TPC0/TEX: 80000049
kernel: nouveau 0000:01:00.0: gr: TRAP ch 13 [007ed50000 Xwayland[1012]]
kernel: nouveau 0000:01:00.0: gr: GPC2/TPC1/TEX: 80000009
kernel: nouveau 0000:01:00.0: gr: GPC2/TPC0/TEX: 80000009
kernel: nouveau 0000:01:00.0: gr: GPC1/TPC1/TEX: 80000009
kernel: nouveau 0000:01:00.0: gr: GPC1/TPC0/TEX: 80000009
kernel: nouveau 0000:01:00.0: gr: GPC0/TPC1/TEX: 80000009
kernel: nouveau 0000:01:00.0: gr: GPC0/TPC0/TEX: 80000009

Second time I was doing random things and I got this

kernel: nouveau 0000:01:00.0: Xwayland[1009]: channel 3 killed!
kernel: nouveau 0000:01:00.0: fifo: engine 0: scheduled for recovery
kernel: nouveau 0000:01:00.0: fifo: runlist 0: scheduled for recovery
kernel: nouveau 0000:01:00.0: fifo: channel 3: killed
kernel: nouveau 0000:01:00.0: fifo: read fault at 0002de2000 engine 00 [GR]
client 0f [GPC1/PROP_0] reason 02 [PTE] on channel 3 [007f82e000
Xwayland[1009]]
kernel: nouveau 0000:01:00.0: gr: GPC2/TPC1/MP trap: global 00000004
[MULTIPLE_WARP_ERRORS] warp 3000d [OOR_REG]
kernel: nouveau 0000:01:00.0: gr: TRAP ch 3 [007f82e000 Xwayland[1009]]

Third time I got this which flooded my log with 500.000+ lines of same thing

kernel: nouveau 0000:01:00.0: fifo: SCHED_ERROR 06 []

I hope this help to find some fix, best regards