Uhh, I would be very interested to see how they plan to accomplish this because current nuclear rocket tech involves blasting radiation out in a manner which would irradiate all debris and craft behind it within low Earth orbit. They would have to make a rocket which reaches interplanetary space first and then uses nuclear, which at that point makes nuclear useful for deceleration to achieve an orbit around Mars. At that point it would technically be the first successful nuclear rocket, however cost/benefit wise it doesn't make too much sense. The research for a reliable rocket was finished back in 1972 with the US nuclear engine program ending in 73.
TLDR: Nuclear rockets were fully developed over 50 years ago, they're very radioactive, practical applications near Earth extremely limited, and it is of this poster's opinion that a nuclear rocket to Mars will be more about research than practical future application.
Edit: I'm a retard, they mean nuclear electric propulsion. Ramping that up to a larger scale will be cool. Good shit