I've just listened to the Perfect Organism podcast on this, and thought about this.
Having the Queen plant it makes no sense, as she has zero time to plant it. They land on the Sulaco. In the landing bay, the Queen skewers Bishop, and emerges from the landing gear of the dropship where she was hiding. She battles Ripley, then gets sucked out the airlock. Therefore, she couldn't have planted the egg.
There's flaws in the theory, but I still favour Bishop. He could've had hidden programming he wasn't aware of that overrode the 3 laws, allowing him to put the egg there, or he could've been remotely controlled by someone at Weyland-Yutani. He had time to get in the nest and grab an ovomorph whilst Ripley and Newt are escaping the nest/Queen. But again, time on the Sulaco is the problem here. As the only way Bishop works, is if he took it up there before coming back for Newt and Ripley, as again, with the Queen's emergence from the landing gear, he had no time to go and hide it. Plus, I'm sure Ripley and Newt would've seen it in the drop ship.
So I'm not certain, but Bishop makes far more sense than the Queen.