It is always a better choice to convert to an image sequence. Read nodes will get bogged down when rendering because the .mov reads can only be single threaded, where as an img sequence can use multiple threads when rendering, making speeds much faster.
1.) hide the postage stamps on the reads of .mov files if nuke is crashing and freaking out
2.) when rendering, if you receive a .tmp error and runs through the timeline without rendering anything, try checking "render in background"
3.) use img sequences in nuke when you can