Liam Boyce gave the home side the lead in the second half from the penalty spot before Funso Ojo, scoring his first for the club, levelled with a close range strike.
A draw was a fair result in a keenly fought match in front of over 17,000 fans at a raucous Tynecastle, by far the biggest crowd since the pandemic began.
Neilson said: “We’re expecting him up either tonight or tomorrow morning.
“It’s been authorised by Liverpool. It is just a case of getting him up and getting him ready.
“I am delighted. I would love it to be a permanent, but he is not one we can get so it will be a loan.
“Today when you look at us we are quite light squad wise. We have got some of the young ones, who need to go out on loan to develop.”
On the match, Neilson, who played down a full-time heated argument with Aberdeen captain Scotland Scott Brown, said: “I thought first half we played really well.
“I thought we were exceptional at times and pressed really high, dominated the game.
“Second half I thought Aberdeen the better team. So it was a game of two halves.
“The fans behind us gave us that push at the start, but we had to keep that going right through the whole game.”
Aberdeen manager Stephen Glass was thrilled with the application his team showed following a tiring midweek Europa Conference League draw away to Qarabag in Azerbaijan.
Glass said: “I’m delighted. The game on Thursday night took a lot out of them. I think you saw second half the energy levels that they give.
“I didn’t doubt them, but I thought the quality and the energy levels today were brilliant.”
However, Glass hinted that a partisan home support helped sway referee Bobby Madden’s mind in awarding the penalty following a coming together between Declan Gallagher and Gary Mackay-Steven.
Glass added: “I haven’t seen it on video yet, but there is a big atmosphere there and I feel like it was the type of penalty that was going to be given today.
“I won’t say which end, but it feels like the type of penalty that was going to be given.”