Can I use Megaton Blower if there's a Stadium in play but my opponent doesn't have any Tools or Special Energy cards in play?
Yes, you can. Discarding the Stadium is not reliant upon discarding any other cards in this case.
Source: Surging Sparks FAQ; TPCi Rules Team (2024-11-07)

Relevant cards

Note: All applicable cards may not be listed below.
SV8_182
SV8_182