United have been linked with Sancho and his Borussia Dortmund teammate and star striker Erling Haaland.
But Neville thinks they will prioritise winger Sancho after they re-signed forward Edinson Cavani on a one-year extension.
"I haven't got the contacts on the inside I used to have so that's my assumption because they've been desperate for Sancho.
"I'm looking at it now and I'm thinking: I think Sancho comes in and I think you've got Sancho that will play on that right-hand side. You've got the backup of Greenwood on that side.
"Up front, you've got Cavani and Greenwood, they'll want Greenwood to come through because I think he's outstanding. On the left, you've got Rashford and Martial and then you've got Pogba potentially can fit in there if he's not in midfield.
"If you sign Kane or (Erling) Haaland as well, I don't think that works for Manchester United in the way they've recruited in the past few years.
"I think it's Sancho and I think that's their business done."