Regis lifted the famous trophy at Wembley after the Sky Blues' thrilling 3-2 win over Tottenham in the 1987 final.
And he fancies Chris Coleman's troops to give Guus Hiddink's Blues a "great game" in Saturday's 12.30pm kick-off.
Regis, who scored 47 goals in 238 games for Coventry, said: "It's going to be a great game and the Ricoh Arena will be packed to the rafters.
"There's no pressure on Coventry and if they can use that, and Chelsea put out an under-strength team, who knows."
Regis feels there is still some magic in the FA Cup, and was delighted to see Portsmouth lift the trophy last season, adding: "For the top clubs, their priority is the Champions League, but for most other clubs and romantics, it's still a fantastic competition.
"We had Portsmouth winning it last year which was fantastic to see and it gives all the other clubs hope.
"It's important to football that lesser clubs can pick up a major trophy."
Regis played in the West Midlands between 1977 and 1994, starting his senior career at The Hawthorns with West Brom and going on to star for Coventry, Aston Villa and Wolves.
He is delighted to see Martin O'Neill's Villans pushing Arsenal all the way for a Champions League place, and admits he'd love to see a boom time for the Midlands region, with Wolves and Birmingham pushing for promotion from the Championship and Albion scrapping to retain their top-flight status.
Regis said: "Martin O'Neill has done a fantastic job this year and is 18 months ahead of schedule.
"He's like Lester Piggott, just seeing the last couple of furlongs now as we enter the final 10 games, and hopefully they can stay up there.
"I fully want every West Midlands side back in the Premiership, like it was in the 70s and 80s where the atmosphere of the area was fantastic."
Both Wolves and Blues got their promotion bids back on track with midweek wins, but Tony Mowbray's Baggies face an uphill struggle to avoid relegation to the Championship after Tuesday's 3-1 defeat by Arsenal left them in bottom spot, six points from safety.
Regis admires Mowbray's footballing philosophy but feels 'silly mistakes' and a 'lack of urgency' have hindered them this season.
He added: "They play a possession style but I would like to see more pace and urgency at times.
"Tony Mowbray's philosophy is right and no teams really dominate them in terms of possession, but I think they do suffer from a lack of quality around the pitch, especially at the back, and silly mistakes.
"I would love them to survive and they've given themselves a chance as they're not cut adrift - they've given everyone that wants to see them stay up hope, and that's a good thing."
At the other end of the table, Manchester United seem on course for a third successive Premier League table having pulled seven points clear of Liverpool and Chelsea following the 2-1 midweek win at Newcastle.
Regis concluded: "Sir Alex Ferguson is a fantastic manager, he's been there, seen it and bought the t-shirt.
"He knows how to manage his side for all 10 months of the season.
"They started off poorly but he didn't panic and all of a sudden they're ahead in the title race, having already won two trophies.
"He must be sitting with his glass of wine thinking 'great, I'm loving football."
Regis was speaking on behalf of Barclays Ticket Office, which is giving fans the chance to win a pair of free Barclays Premier League tickets every 90 minutes throughout the 2008/9 Barclays Premier League season.
You can enter by requesting a receipt from any Barclays ATM or
, Draw 11/4
, Coventry 13/2