Porto produced an impressive performance to win their play-off against Roma, but will face an FC Copenhagen unbeaten in the league this term
The Portuguese club secured an impressive 4-1 aggregate victory over Roma to reach the group stage and have a far stronger European pedigree than group rivals Copenhagen, Leicester City and Club Brugge.
But Nuno was keen to play down suggestions that his charges are set for an easy passage into the knock-out stages.
"The play-off game [against Roma] was held in August," he said. Now we are at a different stage, the team is growing and Wednesday night is a new opportunity and a new challenge.
"The first goal is the game on Wednesday. Favouritism does not guarantee victory.
"We have to prepare well and then go to the field with the commitment and dedication necessary to win.
"It is worth noting that we are in a group with three champions of their respective countries.
"The players know that in the Champions League, nothing is easy and it will be a difficult game against a competitive rival."
Copenhagen have made a strong start to their domestic SuperLiga campaign, winning five and drawing three of their eight games to date.
Stale Solbakken's side successfully saw off Crusaders, Astra and APOEL to reach the group stage for the first time in three years and Nuno insisted there is no danger of the hosts underestimating them.
"We know Copenhagen very well as today all teams know each other," he said. "They are a good team and they will come to Estadio do Dragao undefeated.
"But we are focused on us, we want to continue to grow and show that Porto are very hard to beat."