I am inclined to think that right now your toddler is feeling rushed about this.
He is still asking about the afternoon session you have dropped a few weeks ago. He pesters you in the morning, and that is possibly causing him to feel even more attached to that session than he would have been, ie it is becoming an issue of sorts in his mind.
I'm not sure how, but it would be good to get to the don't offer, don't refuse stage. Then if he feels it is there, he may not pester, and then you are in a better position to be doing things busily, so that he will ask less.
If you just insist on cold-turkey weaning from the morning session, you are likely to have a more upset child. I would suggest that you be up before he is, be very busy, be distracted and say things like wait until I finish this. But them let him nurse. Rather than refusing, him pestering, and you giving in.
Get him eating a solid breakfast before he nurses, if he does not already. That could be one way also that the length of these sessions decreases.
Some people have had success with cutting down the length of a nursing session first before dropping it. eg ensuring it is quick by saying it will stop when you count to ten or something. At first, let him nurse for a bit, and then introduce the idea of counting. Later, start the countdown earlier and earlier in the nursing session.
Possibly, there are even mornings if you know you could go grocery shopping or something early, that you could put him off occasionally with the fact that you have to go to the shops and don't have time right now. Other activities could be offered, with the idea of doing them for a while and nursing later. This is distracting as a method.
It could take a while, but if you want to avoid the chaos you think will happen, I hope these iideas help you.
Thanks for the tips!!
I was thinking more of a session when everyone is ready to be out of bed anyway. I can certainly see why you do not want an hour of a lively toddler nursing and unwilling to sleep again at 3 am.
Some other possiblilities.
Make the nursing session very short, perhaps counting to limit it. Offer water first, then nurse, then put him back to bed. Not with you.
Is it possible that your partner could attend to him for a while at the early morning one instead? Perhaps go and offer a sippy cup of water, in the cover of darkness, very quietly, and matter of factly. And say quietly that mummy is sleeping, can't wake her and so on. Then settle him back to sleep?
I don't know. It can be a difficult time, and I can certainly see why you are saying you do not want the nursing relationship to end with memories of a bad time.