SAO PAULO, April 27 (Reuters) - Brazilian digital bank Nubank said on Monday it will invest about 45 billion reais ($9.06 billion) in the country in 2026, including in office expansion and AI-based platforms and credit models.

* Brazil is Nubank's main market with 113 million clients.

* The investment amount has nearly doubled over the last two years, the lender said in a statement.

* Funds will go toward AI-driven credit models, new product launches, infrastructure expansion, and strengthening its financial base.

* Beyond Brazil, the company plans to expand in Mexico, where it serves 15 million customers, and in Colombia, where it sees "enormous potential."

* Nubank is controlled by listed parent Nu Holdings. ($1 = 4.9678 reais) (Reporting by Isabel Teles; Editing by Gabriel Araujo)