A bit late on this, but I looked back on the Vegeta vs Kiwi fight. This is untrue. He's cocky, sure. But his first act after realizing Vegeta was stronger than him was
trickery and a beam attack. Even before he realized Vegeta was stronger,
he had planned to kill him. Kiwi was only cocky against Vegeta because he had
long been a "rival" of Vegeta and believed he had gone soft due to him concealing his power. With the two being equals in power.
So I don't think it's fair to assume he'd be as cocky against any other opponent in the same way he did against someone he had beef with that he thought had gotten weaker. Given he wouldn't be able to read his opponents power level here, I think he'd just consider him fodder and try to vaporize him with a Chi blast. After seeing it had little effect on him, he'd then become more serious. From there, I think he'd range spam Chi blasts.