I need to overwrite those generated sitemap. is there any way to do that?
Main Sitemap Url https://www.samplesite.com/sitemap.xml
Nested Url for pages: https://www.samplesite.com/sitemap_pages_1.xml
So, every URL's are automatically generated by shopify. How to edit those sitemap urls and nested urls.
You don't edit sitemap files. On a hosted platform like Shopify you accept that they generate correct sitemap files to suit your needs.