How to structure input parameter to object in JS

I have a simple Express API here.
When the user submits the chain param I want to convert the parameter to an object.
Depending on the input the object will have different values
Right now I just have a bunch of if statements stacked

Is there a better practice solution to implement this as this is quite clunky?

app.get('/gettokens/:chain/:address', async(req, res) => {
    const address = req.params.address;
    let chain = req.params.chain;

    if (chain == 'bsc') {
        chain = {
            moralis: 'bsc',
            coingecko: 'binance-smart-chain'
        }
    }

    if (chain == 'eth') {
        chain = {
            moralis: 'eth',
            coingecko: 'ethereum'
        }
    }

    if (chain == 'avax') {
        chain = {
            moralis: 'avalanche',
            coingecko: 'avalanche'
        }
    }

    if (chain == 'matic') {
        chain = {
            moralis: 'matic',
            coingecko: 'polygon-pos'
        }
    }