N.M. Stat. § 45-3-407
Formal testacy proceedings; burdens in contested cases.
In contested cases, petitioners who seek to establish intestacy have the burden of
establishing prima facie proof of death, venue and heirship. Proponents of a will have
the burden of establishing prima facie proof of due execution in all cases, and if they are
also petitioners, prima facie proof of death and venue. Contestants of a will have the
burden of establishing lack of testamentary intent or capacity, undue influence, fraud,
duress, mistake or revocation. Parties have the ultimate burden of persuasion as to
matters with respect to which they have the initial burden of proof. If a will is opposed by
the petition for probate of a later will revoking the former, it shall be determined first
whether the later will is entitled to probate. If a will is opposed by a petition for a
declaration of intestacy, it shall be determined first whether the will is entitled to probate.