England face the Swiss in a crucial Group B match at the Coimbra Stadium at 5pm - having lost against the French, defeat will mean they cannot qualify for the knock-out stages.
Coach Chris faced Switzerland twice in qualifying for the tournament in his role as Ireland's assistant manager - the Swiss won both games to win the group and relegate the Republic into third place.
"Switzerland are a good side," said Chris. "If you asked me who was the strongest, England or Switzerland, I would say England for sure.
"But Switzerland qualified on merit having beaten us home and away.
"They haven't the depth Engand have in regards the squad but on their day they will be able to compete with England, that's for sure."
Meanwhile, it looks like John Terry will come back in for Ledley King against the Swiss despite Ledley's heroics against France on Sunday.
Whatever Sven Goran Eriksson's decision, Chris insisted: "As a player you want to be able to perform at the highest level and there is no higher level than that.
"When you also think that he was up against a team with possibly the three best players in the world was wondeful for Ledley and one he can always look back on and remember."
Chris Hughton agrees with Robbie Keane's warning for England not to underestimate Switzerland this afternoon.