How can I get a contract source code and contract ABI code using Nethereum? For example like here: https://api.bscscan.com/api?module=contract&action=getsourcecode&address=0x0e09fabb73bd3ade0a17ecc321fd13a19e81ce82
Sadly not. This isn't possible as there are many different source codes that can generate the same bytecode. BSCScan / Etherscan / etc all rely on users uploading the source code. Whilst an approximation of the source code that would generate the same bytecode is possible, there's no saying how accurate it would be. All of those blockchain scanner services have APIs so you may wish to look into using one of those.