Klick and BLT

If klick uses his ability to cancel my r1 BLT, can I spend the second charge to add another dice?

Yes, you can do it but there is a difference depending on player order. Klick and BLT abilities trigger at step 2.a of the attack and:

• if the defending player goes first, Klick resolves its ability and then the attacking player resolves BLT ability.

• if the attacking player goes first, BLT ability has to be resolved before Klick and other abilities of the defending player.