England's last one-day international tournament meeting with the Black Caps ended in an eight-wicket defeat at the World Cup in February 2015.
Morgan says that heavy loss was like "men against boys", with New Zealand going on to reach the final.
"It's completely different now, two years down the line," said Morgan.
England recovered later that year to beat Brendon McCullum's tourists 3-2.
Another victory in Tuesday's match, which starts at 10:30 BST, would put them into the Champions Trophy last four, after New Zealand's game with Australia on Friday was abandoned because of rain.
"We've got a completely new team, pretty much," added Morgan.
"A lot of it has to do with confidence. We come into this tournament full of confidence.
"The dominant factor in New Zealand was that they had that confidence, whereas we didn't."
Morgan's side face Australia at Edgbaston on Saturday in their final Group A game.
Steve Finn has replaced injured all-rounder Chris Woakes in the squad and Morgan says the Middlesex seamer was an automatic choice.
"It was backing up consistency in selection and trying to get guys together as a group that we've showed trust in over the last couple of years," he said.
"We've tried to go like-for-like as often as we can. But when we can't, we go for a guy we can throw the ball to at any stage in order to try to make an impact in the game.
"Finny is one of those guys, and I'd have no hesitation in playing him if we felt it was the right thing to do."

A man in his 40s was found dead just after 06:30 GMT at the One-Stop store in Ditton Lane, police said.
Three men, aged 40, 44 and 69 from Cambridge, and a 50-year-old man from Fenstanton have been arrested on suspicion of manslaughter.
A 45-year-old man from Cambridge was arrested on suspicion of grievous bodily harm.
Police said the man who died was from the local area.
A post-mortem examination is due to be held on Tuesday.

The 24-year-old clocked 101.76 seconds to finish behind Slovakia's Michal Martikan and Sideris Tasiadis of Germany in the third leg of the series.
Martikan took victory by 0.69 seconds on the Markkleeberg course to secure the 20th World Cup gold medal of his career.
"The manner in which I did it today is what I'm happy about," said Burgess.
"Third in the heats, third in the semis, third in the final. That consistency is what I had last year and it's what got me a lot of good results."
The fourth leg of the World Cup is in Ivrea, Italy from 1-3 September.
Women's K1
Ricarda Funk (GER)  103.85 (0)
Jessica Fox (AUS)  106.31 (0)
Eva Tercelj (SLO)  109.17  (0)
Men's C1
Michal Martikan  (SVK)  100.88  (2)
Sideris Tasiadis    (GER) 101.57  (2)
Adam Burgess  (GBR) 101.76  (0)
England captain Eoin Morgan says his side have the confidence to beat New Zealand in Cardiff on Tuesday and reach the Champions Trophy semi-finals.
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Five men have been arrested after a body was found at a convenience store in Cambridge.
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Great Britain's Adam Burgess won bronze in the men's C1 at the Canoe Slalom World Cup in Markkleeberg, Germany.