Most *definitely*! I have been a Psych Associate ("Tech") for the past seven years and when people find out I'm in Nursing School the first question they ask is if I am going to be a Psych Nurse. I'm not planning on it (right away, at least), but I have already gotten job offers/promises for after graduation, which isn't for another year!
It's definitely VERY good experience if you're planning on doing Psych Nursing! I couldn't imagine going into Psych Nursing with just the amount of experience you get in clinicals......! Yikes.