Yes, import your walk animation with a new name (e.g. bwd_walk) and set the animation sequence to play with a rate of -1. Then use it for any negative speed.
I have a backwards walking animation the only problem is my speed float is always positive everytime I print it to the screen. Is there an easy way to have it be negative if the player is moving backwards?
copy and paste this, make your blend space from - max speed to max speed, get velocity and multiply by direction, I got this from the shooter demo if this is not clear enough download it and find the anim blueprint of the character pawn.