Tinubu, who took office in May, has embarked on Nigeria’s boldest reform agenda in decades to boost sluggish growth.
The appointment of the acting governor comes after the suspension and arrest of his powerful predecessor at the weekend.
Tinubu inherits economy riddled with huge debt from predecessor Buhari, whose protectionist policies spooked investors.
From the economy to security, Buhari’s legacy will be one of missteps and misdeeds as he hands over power, analysts say.