DeVos cemented concerns about her stance on special education, sexual assault and the enforcement of federal laws.
The final Obama administration tally shows 223 schools under investigation.
Federal and state authorities say Navient misallocated payments, steered people into costly plans, supplied the wrong information and ignored borrowers' pleas for help.
Trump's nominee for education secretary was criticized by some for saying a school used guns to combat grizzly bears.
Nominee for education secretary sidesteps Democratic push for commitments to Obama-era actions focused on the nation's college campuses.
The nominee for education secretary left senators puzzled by denying her documented involvement in a foundation that has funneled millions of dollars to anti-LGBT causes.
Education Secretary nominee Betsy DeVos revealed very little about how she intends to govern an agency that oversees thousands of colleges and universities, and the trillions of dollars in loans and grants that help keep their doors open.
One example: She wouldn't say guns don't belong in schools — and cited a school's need to protect itself from “potential grizzlies.” Bears, that is.
This is how she responded.
An extraordinary exchange at her confirmation hearing as education secretary.
Navient made serious mistakes at every step of the loan collection process, the Consumer Financial Protection Bureau said in a lawsuit.
The school choice advocate seemed unfamiliar with basic terms and policies, including the federal law for students with disabilities.
Ms. Rice, who started life as a janitor’s daughter, helped persuade Congress to provide federal subsidies to tens of millions of needy college students.