Barcelona have the upper hand on Inter in Camp Nou very clearly. I expect them to show a very dominant performance and Inter are also expecting this. Therefore Inter's target would be to take advantage of some chances they could get in the game and to defend Barcelona as hard as possible. They will hope for Barcelona players to have a bad day. Barcelona couldn't even score for two weeks so I expect them to be very willing to win this. It is a critical game for their future in the Champions League as well.
I think Barcelona will win this but maybe it might not be by a big gap.
I also think that Barcelona will try to win the game against Inter Milan at Camp Nou, although it could be by a very narrow score as happened in the La Liga match with Celta Vigo where Barcelona also won narrowly at Camp Nou. In this Champions League group, Barcelona need to work hard and win the match to get second place in the three remaining matches in the group stage in order to ensure themselves qualify for the next round.
It is highly unlikely that Barcelona will win by a big margin against Inter Milan. Because Inter Milan won the home match. They will want to share the points in away matches. So they will play defensive from the beginning of the match. Moreover, Inter Milan played defensively in the first match as well. They made only 5 shots in the entire match. They were very lucky to be able to win. I think we will see similar gameplay in the second leg. Barcelona will need to attack a lot if they want to beat Inter Milan. Otherwise, Barcelona will not be able to get 3 points against Inter Milan.