It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) combined the Maghrib and Isha prayers at Muzdalifah without an adhan, but an iqamah was said for each. And no sunnah or nafl prayer was performed between or after the two prayers.
Hadith Referenceالسنن المأثورة / باب عمارة الأرضين / 438
Hadith Takhrijصحیح بخاری، الحج، باب من جمع بينهما ولم يتطوع، رقم: 1673، صحیح مسلم، الحج، باب الافاضة من عرفات الى المزدلفة، رقم: 703