American Choice and Innovation Online Act This bill prohibits certain large online platforms from engaging in specified acts, including giving preference to their own products on the platform, excluding or disadvantaging competing products from another business on the platform, or discriminating among similarly situated users. Further, a platform may not materially restrict or impede the capacity of a competing business user to access or interoperate with the same platform, operating system, or hardware or software features. The bill also restricts the platform's use of nonpublic data obtained from or generated on the platform and prohibits the platform from restricting access to platform data generated by the activity of a competing business user. The bill also provides additional restrictions related to installing or uninstalling software, search or ranking functionality, and retaliation for contact with law enforcement regarding actual or potential violations of law. The bill establishes affirmative defenses for the prohibited conduct. The Federal Trade Commission or the Department of Justice must designate whether an entity is a platform covered by the bill, and both must carry out enforcement activities. The bill also provides for civil penalties, injunctions, conflicts of interest, a private right of action, and the forfeit of profits for repeat offenders.