Couple of things.
First, he used the strip in his November race with no improvement so the jump up was second time nasal strip.
Second, even if it is the reason for his improvement, how is using a nasal strip to keep soft nasal tissue from collapsing which can happen with horses during strenuous exercise any different from using a circle 8 nose band, tongue tie or special bit to keep the tongue in place to prevent soft palate displacement which can also occur during strenuous exercise? Is soft palate displacement any more natural than collapsed soft nasal tissue?