Is there a way to use the nintendo switch without using a hdtv?

You can just use it undocked. At present there aren't any games that are exclusive to docked/TV mode.

The Nintendo Switch is geared only to run on modern digital TV's through an HDMI connection. If you have an analog TV (which have been discontinued in North America around 2008 / 2009), you will need to have some type of converter to make the A/V signal compatible... which would result in less than desirable results since analog TV's typically run at 240i & generally maxes out at 480p.

It is noted that the Nintendo Switch is a Home-Portable hybrid system, so you can utilize the system without any TV in portable mode.

It only supports HDMI, so unless you have a CRT TV with HDMI ports, you won't be able to use the Switch on your TV. You could also try connecting it to a computer monitor, but the monitor would need to have HDMI ports.

At least you'll always be able to use it as a portable gaming device.