The host has 8gb of ram and the vm is left with standard 1gb, because
somewhere on the Stack I've found a highly upvoted comment about not
assigning vms more than standard amount of resources apart from vram
"because it's enough"
As your experience shows, whatever other people say, 1 gB is NOT enough to run this system, and that is why Chrome is destabilizing and the system is bogging down, this is classic behavior for a system out of memory.
What each system needs is not a generic, it depends on the programs opened, the kernel version, the desktop/window manager, how many programs are open, how many tabs per browser etc.
When I do vm testing, which I do a fair amount of when needed, I only assign 1 gB to systems running a light window manager, when it's kde/gnome etc, I give 2 gB, but that's only for testing the base system, not actually using it, running firefox/chrome/gimp, or other resource heavy applications.
When you're in the vm, you can readily see what is eating up the ram with:
which will give you a list of the top 10 ram consumers, plus the memory available/used totals.
top or htop will also show this information, if you sort the output by memory use. They both also show used/available ram on top:
Mem[... (used to the right)
if you see
Swap[.. being used, that's why it's slow.
If the used percentage is even remotely close to 90% or so before opening chrome, the system will bog down once you open the browser, or whatever else needs ram that isn't assigned and thus forces the system into some type of swap behavior, which I'm not sure how works in a vm.
A quick check shows Kali defaults to using Gnome, and there is no way you can run Gnome with 1 gB of ram. Maybe fluxbox or openbox type window managers, but not kde, gnome, or probably even xfce, unless you don't run any other ram consuming software like chrome/firefox/gimp etc.
Rather than listen to abstract rules for things like how much ram to assign a vm, just test it yourself, and increase the amount until it reaches a point where your workload can perform effectively. There's no formula beyond maybe, if gnome/kde, add 1 gB at least. But that's not a formula either, since the ram consumed can vary release to release, so you want to know this yourself, not rely on rules that can't be made and which should be based on your needs and setup, not a general thing.
To me, anyone using Kali should be aware of such issues to begin with, since it's an expert level distro not meant for casual users.