Melissa Joan Hart is fully backing those sharing their horror stories about Nickelodeon in the 'Quiet on Set' doc -- even though her own time with the network was pretty great.

The actress -- who used to work on Nick for "Clarissa Explains It All" -- went on Meghan McCain's podcast this week to say that while she hasn't seen the doc herself yet ... she believes and supports those who are coming forward to share their stories.

Melissa explains she didn't personally hear any horror stories from any fellow Nickelodeon stars in her heyday while working for them, but says that doesn't negate what's been alleged.

She goes on to describe her own experience with working at Nick -- pointing out she was at the Orlando site while working on her show -- and suggests that might be why nothing bad happened to her. MJH says she had a wonderful experience working as a child actor.

Melissa admits the hours were long -- perhaps too long -- at the end of the day she says she had fun, and the crew protected her -- adding "not every egg in the Nickelodeon basket is rotten."

Melissa made her exit from the network in the mid-'90s for "Sabrina the Teenage Witch" ... well before Drake Bell went through what he did in the early 2000s.

Like Melissa says, she believes everyone who's speaking out ... and 100% has their back. Much like Kenan Thompson, however, she's making clear she was never really victimized.