Only on the Leafs would we speculate
Definitely weird for him to randomly follow another organization at this time unless he has some sort of new connection to them. Wouldn't be the first time a trade in Toronto would be broken through Instagram activity. Just ask DeRozan. Also would not be the first time it's something totally misleading, but this is more weird than most.
Not so sure a pick is what he would go for. Seems like more of a prospect addition in a larger trade, or a prospect-for-prospect swap type thing. However, if the Ducks really like him, then by all means I'd take a pick for Nielsen. He has upside, but we need to start moving out some excess talent and it's going to be tough to fit him in on the Marlies this year. The Marlies could not fit in 8 defensemen last year, and it's not going to be different this year either.
I would be good with getting a 3rd or 4th round pick out of him. If Vesey can get a 7th, Nielsen should be able to get something like that out of a team that really wants him.