I know that "crazy scientist = ENTP" is a safe choice, but Rick seems like an ESTP. He loves science and prides himself being the best at it, but at the end of the day his goal is some Sensory pursuit.
Rick's motivation is attempting to deal with the harsh realisations of being a genius who, through that genius, can do pretty much anything and yet is still subject to the negative nihilism of lacking meaning (a perception of) in anything.
When you strip away the human conceits that are used to buffer against this kind of thinking, sensory indulgence is as meaningful as anything else.
At least in that indulgence there is the illusion of a tangible feedback.
Also it's played for laughs and an inversion of scientist archetypes, in both the cold analytical style and mad, but conceptually brilliant style.
That the drunk at the bar might just have, through extensive experience, a very good insight into the notion of the human condition and then what if he were a scientific genius?
This Rick dude is an ENTP stereotype. Not because he's wearing a lab coat and extraverted. But mostly because he's a nut.


In a nice way. He rescues his evil alter-ego from some kind of hellish realm. Beat that, NFs!!
Rick And Morty - Season 3 Episode 6- (Rest and Ricklaxation) - Video Dailymotion
Rick doesn't rescue his alter ego, he gets tricked by the manifestation of toxic elements of his personality with whom he was trying to reintegrate, removed by alien technology. Interestingly, in that episode, it's revealed that the toxic Rick is the one who actually cares for Morty, since Rick also views his own irrational attachments to family to be a toxic influence.
The whole episode deals with the dangers of trying to do away with or suppress the aspects of a self that are not always palatable. You end up being confident, relaxed and optimistic at the cost of a conscience and being a whole person. Guilt is not pleasant, for example, but it does keep a lot of people in check.
In the context of the episode, though, it would depend on whether you viewed your (now often called) negative emotions as toxic or not.