My two cents:
Chulas are (generally) thrown from the left/reverse. When the ball hits the back wall right where it meets the floor AND the throw came from the left side then the spin causes the ball to 'die' and 'roll out' with no bounce. That is a chula. A right side throw that hits the exact same spot has a different spin so it would 'come out' as opposed to the chula effect......MOST of the time. It is possible that a sidearm right side throw could 'roll out' chula-style. But I agree that 99% of the time, chulas come from left throws.
Chic-chacs could be right or left. But when they come from the left it is from a costada shot (shoulder height throw), not your typical underhand reverse throw. A right side chic chac is much more common. Rebotes can chic chac....because they either come from the right side or left side shoulder height throws (similar to costado).