From the second week of December, the lender will offer the higher LTV loans to include purchase and customers who are home movers.
At the same time, the lender will also remove the temporary ban applied to fully gifted deposits.
Under 90 per cent LTV mortgages, borrowers can take up to £500,000 over a maximum 25-year term.
Rates will be level with those on offer to first-time buyers, including 3.49 per cent for a two-year fixed mortgage with a product fee of £999.
Existing mortgage members remain able to borrow up to 95 per cent on a like-for-like LTV basis, with no LTV restrictions on those looking to switch deals and rates priced the same or better than new business equivalents.
Nationwide re-entered the 90 per cent LTV market in July with restrictions on criteria, which it said protected service and enabled it to lend responsibly.
Henry Jordan, director of mortgages at Nationwide Building Society (pictured), said: “As a mutual, owned by our members, we aim to balance supporting first-time buyers into a home of their own with the need to lend responsibly.
“Given the uncertainty created by the pandemic, our re-entry into 90 per cent LTV lending back in July was deliberately cautious and included enhanced criteria.
“Four months on, we are increasingly confident in our approach and so are delighted to be able to expand our support for the market to include home movers while removing some of the temporary criteria for first-time buyers, making it easier for parents to help them take their first step onto the housing ladder.”