With sixteen on the roster, everyone can't play. Period. These last two games, yes, if done correctly, which Tim failed to do last night. By now we all know who is ready for playing time in the closely contested games. We are trying to win them, not reward everyone for practicing hard. He needs to use the players who can win the game.
If it is more of the same after the next two or three conference games, then he should definitely switch positions with Nadine. I would think that she would have to be a better manager of talent than what Tim has shown. It would be very hard for her to be worse. Maybe she could salvage the season for the players. They deserve better.
The team could still use what Tim has already implemented on offense, but Nadine needs to manage the game instead of Tim (call the timeouts, make the substitutions, final say on play-calling using Tim as per her discretion). Tim seems to be perfectly suited for the role of assistant, providing support for off/defensive sets/plays, teaching detail, giving input. From where I sit, he does not appear to be a good manager.