The 19-year-old has been thrust into the first-team fold at Old Trafford due to a defensive injury crisis severely hampering Louis van Gaal's early reign.
Jonny Evans is one of the missing defenders in United's squad, which has seen McNair make three first-team performances.
Evans' continued absence with an ankle injury means he is still awaiting his first appearance of a Euro 2016 qualifying campaign which sees Michael O'Neill's side top Group F with three wins from as many games.
"I've been hugely impressed with Paddy - he's come into a difficult situation at Manchester United and there is a lot of media attention," O'Neill told the Irish FA's official website.
"The manager has come in and spent a lot of money so it is encouraging to see the likes of Paddy given a chance.
"He's played in difficult circumstances, with the defence a bit makeshift at times and it's difficult for a young player to come into that.
"But he's acquitted himself very well, he's around the Manchester United first team and I'm looking forward to having him in the squad."
Northern Ireland squad in full:
Goalkeepers: Roy Carroll (Notts County), Alan Mannus (St Johnstone), Michael McGovern (Hamilton Academical).
Defenders: Chris Baird (West Brom), Craig Cathcart (Watford), Aaron Hughes (Brighton), Gareth McAuley (West Brom), Luke McCullough (Doncaster Rovers), Ryan McGivern (Port Vale), Conor McLaughlin (Fleetwood Town), Ryan McLaughlin (Liverpool), Paddy McNair (Manchester United).
Midfielders: Chris Brunt (West Brom), Sammy Clingan (Kilmarnock), Steve Davis (Southampton), Corry Evans (Blackburn Rovers), Paddy McCourt (Brighton and Hove Albion), Niall McGinn (Aberdeen), Oliver Norwood (Reading), Ben Reeves (MK Dons).
Strikers: Will Grigg (MK Dons), Kyle Lafferty (Norwich City), Josh Magennis (Kilmarnock), Billy McKay (Inverness Caledonian Thistle), Jamie Ward (Derby County).
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