Nate Richie is one of the passengers who survived the Delta plane crash in Toronto ... and he's scoffing at the airline's $30,000 offer.

Nate tells us he hasn't been able to sleep since Monday's crash and he doesn't think the $30K offer extended to survivors is remotely close to the toll the incident is taking on his mental health.

He has hired attorney Ardalan Montazer, and he doesn't believe he'll ever fly again ... that's how traumatized he is by the crash landing.

Nate's actually driving back to Florida instead of flying home ... telling us it's been days since he's seen his family, and he's reached out to a therapist for help.

As we reported ... Delta is offering to cut $30K checks to the dozens of people who were on the flight, and the airline says the money comes with no strings attached -- and anyone who accepts the payment can still take legal action against the airline.

Nate says it's all too much for him to deal with right now ... telling us he needs more time after a brush with death.

He gives us a play-by-play account of the doomed landing ... and says he thought his life was over when he was hanging upside down in the plane with jet fuel wafting through the air and running down the windows.

Passengers and crew were able to escape ... but Nate says moments after he got off the plane there was an explosion near the door where he exited.