Answer:
That was the worst television program Nick had ever seen.
Step-by-step explanation:
The correct modifier here is the superlative: worst. This modifier makes sense because it helps describe the fact that the television program is the most distasteful one he had ever seen.
Worse is the comparative form of the modifier. For Ex: "Nick did not enjoy the movie his sister chose, but the one he chose was even worse." It is meant to compare the quality or experience of two objects.