When I boot without X or hit Ctrl+Alt+F1 I have very low screen resolution.(large font)
Normal for the screen is 1920x1200.
Can I change it?
Does it have to do with Nvidia?
colechristensen is correct but it should be pointed out that you append
You will then be confronted with a list of possible VGA modes, but most likely 1920x1200 will be absent. This is a common bug in the VGA BIOS of graphics cards not listing resolutions higher than 1280x1024, and the only easy solution is to use the open-source video driver. With the open-source driver KMS(kernel mode-setting) will be utilized, giving the kernel access to "fancy" modes like 1920x1200. Without KMS, you can easily access those fancy modes (AFAIK) only in X.
Edit the kernel arguments in grub.conf (or menu.1st, wherever the grub config actually is).
The first time you run is insert the argument vga=ask. This will prompt you with a list of possible resolutions the next time you boot. Try them out until you find one you like, then set that in your grub config. I believe mine is vga=0x344.
EDIT: Apparently ubuntu is using something more complicated than I'm accustomed to.