Yes, you supposedly can.
If you trade a hidden ability Pokemon from another cartridge, you can breed it to get another Hidden Ability Pokemon. Trading is available after beating the 1st Gym. For breeding guide; i.e passing down abilities, moves, natures, available here.
Another option is the Dream Radar. Dream Radar is a game released on the 3DS which you can install for free via the E-Shop. You will be able to capture Pokemon and collect items which can later be transferred to your mainline Black/Black 2 and its respectable counterparts. The Pokemon you capture here has a chance of being a HA Pokémon. The 3DS E-Shop is only available up to March 2023, so grab it while it lasts!
I hope this helps!
Source 1 (Breeding Guide)
Source 2 (Dream Radar)
