The most important relationship in any nonprofit is between the board chair and executive director/CEO—some good resources here:

https://boardsource.org/board-chair-chief-executive-communications/?utm_campaign=R%2BS&utm_medium=email&_hsenc=p2ANqtz-9IDj53bB2G8vgke6kJqsMjPpvsYD5JTasWzZMrBPgqEv4pjIhfC3xnfb3IDqvUCpqBV7JtnBrEWGk2k9x5VInKs9Bp2lKcvGulFAq2ZnxEs8udwmA&_hsmi=60380493&utm_content=60380493&utm_source=hs_email&hsCtaTracking=1fd054f8-7a44-42b1-8ed6-22dc1e1e9a75%7Ced4ffe88-3bc0-4dea-a103-1931063a33c5

https://boardsource.org/board-chair-chief-executive-partnership/?utm_campaign=R%2BS&utm_source=hs_automation&utm_medium=email&utm_content=60353960&_hsenc=p2ANqtz-9OM2Dn6A2naz4rEbQJd1g73oETzWe49FYWJ3XWaf2LdmOaWVF6Zg5TslQb0RH2WTxAUaNMiqOj2pp-y_PIKdccRgP-vtGMm_vp1AeHGrDghTz0VTg&_hsmi=60353960