I don't think that Chinander or anyone on the staff would say that they want to be "relying on turnovers to have a successful defense," but it's definitely a point of emphasis. When I mention more risk and more reward, I don't mean crazy gambling chances; I mean CBs in full press coverage, aggressively trying to take away the strengths of opposing receivers and hoping that a ball gets thrown in his direction to go make a pick. Like Fischer and Chinander said, knocking a ball down is a safe play, but they want interceptions. If a CB uses good technique and is in good position, going for the interception but not getting one will still result in a pass being knocked down.
As far as the ball-hawking tackles, they're still teaching simple, fundamental tackling, but they're including a poke at the ball when the RB or WR is running and a strip of the ball when it's a QB being sacked. Those things shouldn't result in any more negatives.
As much as anything, it's a mentality of being aggressive and looking to score while on defense versus a passive, bend-but-don't-break mentality. If you watch the UCF defense in the Peach Bowl, they're getting their butts handed to them in the 3rd quarter, but they continued with some aggressive blitz calls, and eventually they got two picks late in the game, including a pick-6. The UCF defense did not have to return that pick for a TD to win the game because their offense was very effective, but notice how--after that pick-6--the defense suddenly wasn't tired anymore? A good S&C program will take you a long way, but it was that aggressive edge at the end of the game--when they should have been more gassed than they were in the 3rd quarter--that gave them their legs and their breath back.
The blitz packages are probably the most risky part of Chinander's defense, but he's an incredibly high-IQ guy who takes good chances with high rewards. Sometimes, a blitz that doesn't work is still enough to steer the opposing offense's play-calling away from stuff you don't want to see against your defense, and that's the type of response that the Nebraska coaches want to eventually dictate. McBride did the exact same sort of planning and calculations and gambling in the 90s, and we loved him for it because it worked on the big stage when it mattered.