What I saw was a P-47, closely followed by a Nikki, chasing an La-7. Your Spit IX is above and in a position to dive on the La-7. The 47 makes his pass, the La dodges. You have moved into the lead position now, arguably jumping in front of the Nikki in pursuit.
Now this is a little dicey. Had it only been the Nikki in pursuit the the La could have simply run away. Your Spit (with superior E) forced him to turn or die. From this point on there was nothing for him to do but to run back to the Flakpanzer, but your Spit was all over him. I can see shots landing and the moment is ripe. At this point the Nikki clearly positions itself in front of you for the shot, forcing you to kill yourself.
Judgement: toss-up. AmOn could argue he was chasing first (he was). You can argue the kill was all but yours (it was), but there is no denying he jumped in front of your plane.