I just listened to a video in which the speaker said "I'm going to be talking about....". Can we change that to "I'm going to talk about..."?
[1.] "I'm going to be talking about...."
has a different meaning from
[2.] "I'm going to talk about..."
 and  differ in aspect (i.e. the internal temporal structure of the event). In  the speaker is focussing on the talking as an ongoing (continuous) event, whereas in  the focus is on the talking as a single, whole event.
Both forms are correct, and refer to the event in different ways. You could change from one to the other but you'd be talking in a slightly different way about the event.