Access nested struct withing Solidity.

ReadNestedStruct.sol

// SPDX-License-Identifier: WTFPL
pragma solidity ^0.8.19;

contract NestedStruct {
    struct Inside {
        address a1;
        address a2;
        address a3;
    }

    struct Outside {
        uint256 num1;
        bytes32 byte1;
        address a4;
        address a5;
        bool bool1;
        address a6;
        mapping(uint256 => Inside) insides;
    }

    Outside internal outside;

    function setValues() public {
        outside.insides[1].a1 = address(1);
        outside.insides[1].a2 = address(2);
        outside.insides[1].a3 = address(3);
    }

    function getter(uint256 idx) public view returns (address, address, address) {
        return (outside.insides[idx].a1, outside.insides[idx].a2, outside.insides[idx].a3);
    }
}