Was it even charged as a felony?
Pretrial Diversion is sometimes called a deferred prosecution.
As long as you completed the terms set forth by the judge then the charged should have been dismissed meaning that its like the whole thing never happened.
(In most states you only get one of these and only on your first charge)
As long as the charges were dismissed then there is no reason to have to put it on your CHP application.
You should contact a lawyer in you area (prefablly county) that is 2A friendly for concrete advice.
And by the way: Welcome to the forum