Use a Doberman, or an assault rifel on maximum level.

What fred said, I used a doberman at range. Look, part of it depends on your difficulty settings, what food buffs are working, what tier your armor is and what level it is (+1 -+10). I play a custom game that is only on a hard level and had no issues with her, although she hits hard. I don't have all my equipment hardened, not all my gear is tier 5, and not everything is plus 10, but double check your coils on gear and maybe swap out for more resistances. Maybe take a poison drink.

Put heals on your bar, bring more than one doberman and put it on your bar (so you don't have to waste time repairing and don't get a drop off in damage as the gun wears down). I like to use the candy bar and heal pills, because they are easy to find and cheap to buy. Maybe make sure you have leech stats on equipment. I like added head shot damage, but that is me. with stability dumping a full mag in its head isn't hard while it is still.

You dont get headshot bonus by shooting her head. The glowing green bit in her abdomen is the weak point. Crit/headshot build melts her.

On Legend difficulty, NOVA can kill me with one hit.

dodge, crossbow shooting,
then
dodge, crossbow shooting,
finish

Thanks for all replies!