Go to Walmart.GeekSeller.com > Tools > Insights. There are filters allowing you to find specific products, but we suggest to start with a default filter sorting products from those largest difference Your_Price - Buy_Box_Price.
You can use this section to analyze your prices and adjust them from this page to make your prices more competitive.
Warning: there is a limit on Walmart API of 10 submissions of price adjustments from this page per hour. Also submission of prices works only for published products and it takes time for Walmart to update your prices (even few hours).