The Hornets had Lewis McGugan to thank after his excellent second-half free-kick cancelled out Andy Reid's opener to share the spoils at Vicarage Road.
Zola's men remain unbeaten after their opening four Championship games and the 47-year-old believes that the result against Forest was a positive one.
"I think it was a good game for the spectators and the TV," he told Sky Sports.
"It was very much one side to the other, one side to the other. I think the result was good although they had great chances.
"I think we had good chances as well in the second half. It was a close one to be honest but we did very well. I was really impressed by the performance."
Forest could have gone into the break with a two-goal lead after Henri Lansbury's strike cannoned back off the post, but Zola says he was unfazed by the visitors' pressure.
"I wasn't worried in a sense because I knew because the best of my team was yet to come and I knew we were going to do more in the second half," he said.
"What I didn't expect in the second half was that there would be so many chances that we allowed them to have. That was the thing that made me think a little bit.
"I think we have a good, strong squad. We are improving as a team and we have a few issues to sort out but I can't complain, the results have been good so far and we look forward to keeping improving too."