Only you know your risk tolerance. If you have mission critical meetings pre departure from YYZ which stop you from booking the earlier flights and you understand that MSP-NRT is once daily, then by all means go ahead and book a 1-hour connection.

But, if you have any flexibility on departure, I would book any of the 3 earlier departures xYYZ.

DL requires you at the departure gate for NRT no later than T-30. Thus, you have 30 minutes from wheels locked on the inbound to the gate reader for the NRT flight in the event your NRT flight is in danger of an oversell. That cuts it way too close for ordinary circumstances.