Tomonari Nishikawa's films explore the idea of documenting situations/phenomena through a chosen medium and technique, often focusing on the process itself. His films have been screened at numerous film festivals and art venues, including Berlinale, Edinburgh International Film Festival, Hong Kong International Film Festival, International Film Festival Rotterdam, London Film Festival, Media City Film Festival, New York Film Festival, Singapore International Film Festival, and Toronto International Film Festival. His film, sound of a million insects, light of a thousand stars, received the grand prizes at Curtocircuíto International Film Festival and Arouca Film Festival in 2015, and his film installation, Building 945, received the 2008 Grant Award from the Museum of Contemporary Cinema in Spain. In 2010, he presented a series of 8mm and 16mm films at MoMA P.S.1 Contemporary Art Center, and he has been an artist-in-residence at Headlands Center for the Arts, Liaison of Independent Filmmakers of Toronto, and the MacDowell Colony.
Since 2006, Nishikawa has been curating screening programs for various venues, including Early Monthly Segments in Toronto, Segal Centre in Montréal, and Yebisu International Festival for Art & Alternative Visions in Tokyo. In 2010, he was appointed as a screening program consultant for the Aichi Art Triennale in Japan, and he served as a juror for the 2010 Ann Arbor Film Festival, the 2012 Big Muddy Film Festival, the 2013 dresdner schmalfilmtage, and the 2018 Milwaukee Underground Film Festival. He is one of the co-founders of KLEX: Kuala Lumpur Experimental Film, Video and Music Festival and Transient Visions: Festival of the Moving Image.