Technically, Yes, I do think that someone who has fought supervillains in the street can beat someone who was a secret weapon in a war.
A lot of soldiers were scared to death of Bucky and Captain A. Most ran. Nightwing has fought toe to toe with more challenging opponents. Yes, even more challenging than the Red Skull. Red Skull wasn't very impressive back then. Even though Nightwing hasn't won every fight, he's really proved himself to be his own man.
I know how impressive Winter Soldier is and I think in one day's prep or even in a few hours prep he could definately tip the scales but in a impromptu fight Nightwing is going to show him what a batboy can do.