Chappell, who joined the county in the winter of 2018, was his side’s leading wicket-taker in the 2020 Bob Willis Trophy with 15 scalps.
The 24-year-old was named the Emerging Pro Player of the Season, having assumed a leadership role with the red ball in the absence of more senior seamers.
With that challenge safely negotiated, Chappell is eager to continue his development ahead of the new season.
“Last season was a big one for me – I feel like I found my rhythm and my confidence early on, and everything just snowballed from there,” he said.
“I believe I’m a much better bowler for the work that Pete (Peter Moores) and Shiney (Kevin Shine) did with me over last winter, so I’m really excited to see how I can push forward again over this close-season.
“To take the new ball so regularly, and to be a senior seamer in the side, isn’t necessarily a position I thought I’d find myself in last summer, but I loved every minute of it.
“The great thing about playing at Trent Bridge is the wealth of experience you can lean on and learn from – from the coaching staff to the likes of Bally (Jake Ball), Fletch (Luke Fletcher) and Broady (Stuart Broad).
“That’s really helped me over my time here, and I’m sure it will continue to do so over the next two summers.”
Chappell is a five-time England Lions international and a graduate of the ECB’s pace programme, under the stewardship of Shine during his time as fast bowling lead in the national setup.
“There’s no doubt that Zak is the kind of player that rises to a challenge, and he showed that last summer through taking big wickets and bowling important overs,” said Head Coach Peter Moores.
“He displayed the talent we always knew he had, alongside consistency and no little fighting spirit.
“Perhaps most crucially, he’s learned more about the demands of bowling a large volume of overs – and having that experience whilst he’s still in the early stages of his career can only serve him well.
“The challenge next year will be to continue on that upward trajectory. With the quality we now have at our disposal in our fast-bowling stocks, the first step on that road will be for Zak to fight for a regular spot in the side.
“Knowing Zak as we do, he’ll give it everything he’s got.”