Brown has backed 20-year-old Nowell to win selection for Stuart Lancaster's revised Elite Player Squad for the RBS 6 Nations, offsetting England's growing injury troubles.
England's head coach will name his Six Nations squad in the new year, but must omit long-term backline injury absentees Marland Yarde, Ben Foden, Christian Wade and Manu Tuilagi, with doubts remaining over Brad Barritt and Joel Tomkins.
Forwards Tom Croft, Geoff Parling and Alex Corbisiero are all out of commission, with Mako Vunipola still a question mark.
England and Harlequins full-back Brown believes in-form Saxons squad member Nowell is the right man to fill the void.
"It's great to see guys coming through, and showing they can replicate it on the big stage," Brown said of the fast-improving Nowell.
"Jack Nowell has been playing extremely well in the last few weeks, especially in those two games against Toulon.
"So I'm sure he'll get his opportunity.
"Stuart has shown that players will get their opportunity, if they deserve one.
"Unfortunately there have been some injuries, so it looks like he may get his chance in the near future, and he's certainly been in the form to push hard for that.
"So it's great for English rugby just to see these guys coming through and putting their hand up."
Harlequins host Exeter at Twickenham in Saturday's Big Game 6 Christmas Aviva Premiership fixture.
Financial derivatives trading company IG are lead sponsors for the match as part of their Brighter Together campaign.
Brown expects a fierce encounter against the robust fifth-placed Chiefs, especially with just one point separating the sides and Quins still commanding fourth spot.
"Luke Arscott at full-back is another who has been going well for Exeter, and they've started to play a great brand of rugby, to add to their impressive tight game," added Brown.
"It's going to be great for the spectators, to watch us chuck the ball around, go toe-to-toe."
Harlequins academy graduate Brown first broke into the England side in 2007, only to fall out of favour between 2008 and 2012.
Now a mainstay under Lancaster, Brown praised the current England boss' open mind when it comes to selection.
While Lancaster is confident in promoting youth, Brown said he is also careful never to write anyone off.
Sale's talented playmaker Danny Cipriani could fall into that bracket, seemingly ready to put previous troubles behind him and complete his rehabilitation.
Cipriani could be back in the England frame, after winning the last of his seven caps in 2008.
Brown said Lancaster's refusal to disregard form men whatever their past can help England's long-term drive towards Rugby World Cup 2015.
"It took a long time for me to get back in," said Brown, of his four-year gap in England duty.
"I was lucky to have worked with Stuart in the Saxons so he knew what I was about and how desperate I was to get back in.
"It's great that the three to four years I was out of the English set-up, all the hard work that I put in paid off.
"It does take a lot of hard work and effort, but it's all worth it.
"It took a couple of years for me to get a chance at full-back, I've had that now and it's about pushing on.
"No one's place in the squad is secure, and that's important.
"Lots of players will be looked at, and that benefits everyone, especially building towards the World Cup."
IG, the financial derivatives trading company, are lead sponsors of Big Game 6 and as part of their "Brighter Together" campaign will be offering fans the chance to reveal their inner Harlequin at Twickenham Stadium on December 28.