When Barry confronts Firestorm near Dr. Stein's home, Barry requests that he does not "flame on." This is the catch phrase that Johnny Storm (The Human Torch) of the Fantastic Four shouts when he fully ignites his body, just as Firestorm does in this scene.
Barry says that he and his date are going to see Mal Duncan. Mal Duncan is known in the DC Universe as Herald, a hero who uses his horn to open up portals.
The episode title "The Nuclear Man" is based on Firestorm's nickname, The Nuclear Man.
The technology put on Firestorm is the symbol for Firestorm in the comics.
Cisco wears a T-shirt that references The Big Bang Theory (2007), perhaps as an homage to Sheldon who regularly references The Flash.