You can enter patterns with wild cards in Schematic Editor / File / Schematic Setup / Project / Net Classes but this mostly relies on your nets being labeled. You can use a pattern that coincides with the auto generated net names, but that probably does not make much sense.
The other method is by adding net directive labels, but you have to do this for each individual net, and that makes a bit of a mess of the schematic (you can hide these directives). Not too long ago KiCad used to work with another method of putting nets into net classes. That method was more intuitive, but also more limited. This new method is now usable, but not fully developed yet. In KiCad-Nightly there are already some new features of using netclass directives to assign a netclass to multiple nets. See: