Hi , I have a similar issue, where my Identity provider only supports Authorization Code flow and by default express-openid-connect is using Authorization code flow + PKCE. Hence I am also getting error related to nonce:
BadRequestError: nonce mismatch, expected 1qc1TV6mYBObxn3Ab5CVxLbk7-I-RJP6SkiL6a_BD9U, got: undefined
at callbackStack (\node_modules\express-openid-connect\middleware\auth.js:120:31)
at process._tickCallback (internal/process/next_tick.js:68:7)
I want to get rid of this default behaviour and use only Authorization code flow. Any pointers for how to achieve this ?