I'm pretty sure the nukes comment was hyperbole. I don't honestly think the man wants to blow up his own country.
But, the underlying desire expressed by Rep. Swalwell for forceful confiscation of citizens' arms by overwhelming martial force is the disturbingly genuine part.
The "joke" about nukes only shows how badly he's failed to think through the legality, feasibility and desirability of such a planned seizure because, well, it would require a law to be passed that wouldn't immediately be stayed and then countermanded by the USSC, that the law enforcement agencies tasked with such a massive undertaking would have the manpower, let alone personal and political desire, to carry it out BEFORE having to take casualties, the fact there is no master list of who owns guns in this country, the fact the black market would just keep supplying them... and on and on and on.
The end result of the gun grab movement isn't any concrete changes in crime or gun numbers, it is, and always has been, about blatant political virtue signaling, the fact that something you disapprove of has been made illegal is the only goal, not the fallout, intended or otherwise, that comes with it. They want another round of Prohibition, ignorantly and arrogantly believing they can win this time where the previous attempt failed. Why? Because they're on the RIGHT side of history!
They want their legacy of being the one to codify into law what all the right thinking people have known for years... that guns are evil!