Amends the Property Tax Code. Provides that certain property may be certified by the Department of Revenue as containing a mega project. Provides that a "mega project" is a project with respect to which a company makes a specified investment during a specified investment period. Provides that the mega project property is eligible for an assessment freeze. Provides that mega project property may be granted an abatement. Provides that a company that operates a mega project shall enter into an agreement with the municipality in which the project is located to make certain special payments. Amends the Use Tax Act, the Service Use Tax Act, the Service Occupation Tax Act, and the Retailers' Occupation Tax Act. Provides that qualified tangible personal property used in the construction or operation of a mega project is exempt from the taxes imposed under those Acts. Effective June 1, 2023.