Rabbi Juan Marcos Bejarano Gutierrez of Dallas Texas founded Chavurah Zohar Yisrael of Dallas. According to that website:
The goal of Chavurah Zohar Yisrael was to serve Jews living in South Dallas and North East Dallas Counties. To meet the needs of our members and to serve Jews in typically under represented Jewish areas, we developed a “mobile” synagogue with rotating services to reach Jewish families that would otherwise lose out a vibrant Jewish experience.
Rabbi Gutierrez is publishing many Spanish-Portuguese (Sephardic) songs on his YouTube channel, such as the beautiful tune of the Adon Olam below.
His signature book based on his doctoral dissertation at Spertus is “Secret Jews: The Complex Identify of Crypt-Jews and Crypto-Judaism”, as shown below and available on Amazon.
Wikipedia gives two definitions for Nusach. One is the style of a prayer service (or “rite”) (Nosach Teiman, Nusach Ashkenaz, Nusach Sefard, Nusach Edot Hamizrach, or Nusach Ari); another is the melody of the service depending on when the service is being conducted.
Another site for learning about Spanish-Portuguese Nusach is https://sites.google.com/site/shaarhashamayimlondon/, based on music from the famous Bevis Marks Synagogue in London. That site contains almost the entire cantorial repertoire of the Spanish and Portuguese Jews’ Congregation of London – “Kahal Kadosh Shaar Hashamayim” – which was established in 1656 and is the oldest Jewish community in the British Isles.