Bashiru delivered a memorable performance on her first start of the tournament, scoring twice to help Nigeria reach the final of the competition for the first time in history.
After a goalless first half, the Flamingos returned with renewed attacking intensity and broke the deadlock in the 56th minute through Queen Joseph, who finished after Oluwakemi Adegbuyi's effort was blocked.
Nigeria doubled their advantage in the 71st minute when Bashiru produced an excellent finish to make it 2-0, with Joseph providing the assist.
The young forward completed her brace nine minutes later, finding the back of the net in the 80th minute following a well-worked team move involving Oluebube Umejiaku.
Brazil managed to pull one goal back in the 89th minute through Greise Kelly, but the late consolation could not prevent Nigeria from securing an impressive 3-1 victory.
Bashiru's two goals and overall contribution earned her the official Player of the Match award from FIFA.
Bashiru makes first start count
The award represents a major personal achievement for the Nigerian youngster, who had played only 73 minutes across the Flamingos' previous six matches without starting a game.
Head coach Akeem Busari's decision to include her in the starting line-up against Brazil proved decisive, as she delivered the performance that helped Nigeria reach the final.
Speaking after the match, Bashiru expressed her happiness at making her first start and contributing to the team's historic achievement.
"Today was my first start, so I'm so happy, I'm so excited," she told FIFA.
Flamingos prepare for historic final
Nigeria's victory over Brazil made them the first African nation to reach the final of the FIFA U-17 Women's World Cup.
The Flamingos will now face Japan in Saturday's final as they aim to become the first African country to win the competition.
Bashiru will be hoping to maintain her impressive form and help Nigeria complete a memorable campaign by lifting the trophy in Morocco.