Even if the construction of that sentence is not that simple. Try to identify essential part. There, the subject is "Nous" because we both look like something. The verb is obviously "ressembler". Then the complement, what are we looking like ? "nous". "Nous ressemblons à nous" but we can't say that in french. So now the hard part : When the subject is the same as the complement (pronoun), we need to use "la forme pronominal" basically, the verb become "se ressembler". And the reflexive pronoun "Se" change with the subject. Je me ressemble (= I look like myself.) Tu te ressembles (= You look like yourself) Il se ressemble (= He looks like himself) Nous nous ressemblons (= we look like ourselves) Vous vous ressemblez (= You look like yourselves) Ils se ressemblent (= They look like themselves) So the correct sentence is "Nous nous ressemblons".

When the resemblance is strong, there are also useful expressions: - ils se ressemblent/nous nous ressemblons/on se ressemble comme deux gouttes d'eau - c'est le portrait craché de son père