This actually requires no code! Just a warning that a push block feature is upcoming.

1. Create a move Under player conditions, check the box of blocking, I reccomend disabling the other condition other than blocking. This will make it so you can only preform the move when blocking. This move file the preparation for the push block.
Alternatively you can make the "block" basic move as a move file.

2. Set a chain set the condition as "counter" and create another move file (being the character pushing back). This will cause your character to preform another move when hit in this state.

3. In the move file you just created, give the character invincibility or super armor on startup. This is so they don't get hit while they are pushing back resulting in the move getting interrupted.

4. Under active frames there is a applied for option. Adjust that to fit with the amount you want to push the opponent back.

Apologize if I cause issues I only have a month of experience with UFE.