Background
There are five levels of Autonomous administrative divisions in China, namely
- Province - Autonomous Regions
- Prefecture - Autonomous Prefectures
- County - Autonomous Counties/Banners, Ethnic Districts
- Township - Ethnic Town/Township/Sumu
- Village - Ethnic Village
Strictly speaking, "Ethnic" administrative divisions in level 3-5 are not considered "autonomous" by law. However, for the purpose of this answer let's ignore this caveat.
Note 1: This answer deals with Township-level and above only, as there are simply too many villages to sift through!
Note 2: Some three-level deep examples are non-continuous, which I believe are not against the spirit of the question.
Note 3: At county level and above, there are official and established transliteration conventions for place names that originated in languages other than Chinese (example: Kashgar 喀什). However, it is extremely difficult to find such conventions for names of townships. As such, townships are transliterated in Pinyin here (example: Kekeyaer Kirghiz Ethnic Township 科克亚尔柯尔克孜族乡).
UPDATED transliterations for township names from the following sources,
- NGA GEOnet Names Server (GNS)
- EKI Place Names Database (KNAB)
- 中国地名词典 (Zhongguo diming cidian), Shanghai Lexicographical Publishing House, 1990
Note 4: Tacheng Prefecture and Altay Prefecture are administratively under the sub-provincial Ili Kazakh Autonomous Prefecture.
Winners (four-level deep)
Xinjiang Uyghur Autonomous Region (新疆维吾尔自治区) (2)
Changji Hui Autonomous Prefecture (昌吉回族自治州)
Mori Kazakh Autonomous County (木垒哈萨克自治县)
---- Danangou Uzbek Ethnic Township (大南沟乌孜别克族乡)
Ili Kazakh Autonomous Prefecture (伊犁哈萨克自治州)
Qapqal Xibe Autonomous County (察布查尔锡伯自治县)
---- Miliangquan Hui Ethnic Township (米粮泉回族乡)
Honourable mentions (three-level deep)
Xinjiang Uyghur Autonomous Region (新疆维吾尔自治区) (30)
Kashgar Prefecture (喀什地区)
Taxkorgan Tajik Autonomous County (塔什库尔干塔吉克自治县)
---- Kokyar Kirghiz Ethnic Township (科克亚尔柯尔克孜族乡)
Changji Hui Autonomous Prefecture (昌吉回族自治州)
Changji City (昌吉市)
---- Axili Kazakh Ethnic Township (阿什里哈萨克族乡)
Fukang City (阜康市)
---- Sangonghe Kazakh Ethnic Township (三工河哈萨克族乡)
---- Akkol Kazakh Ethnic Township (上户沟哈萨克族乡)
Hutubi County (呼图壁县)
---- Tasbaspaldak Kazakh Ethnic Township (石梯子哈萨克民族乡)
Manas County (玛纳斯县)
---- Qingshuihe Kazakh Ethnic Township (清水河哈萨克族乡)
---- Taxihe Kazakh Ethnic Township (塔西河哈萨克族乡)
---- Hankazitan Kazakh Ethnic Township (旱卡子滩哈萨克族乡)
Qitai County (奇台县)
---- Wumachang Kazakh Ethnic Township (五马场哈萨克族乡)
---- Qorin Kazakh Ethnic Township (乔仁哈萨克族乡)
---- Daquan Tatar Ethnic Township (大泉塔塔尔族乡)
Bayingolin Mongol Autonomous Prefecture (巴音郭楞蒙古自治州)
Yanqi Hui Autonomous County (焉耆回族自治县)
Hoxud County (和硕县)
---- Uxxaktal Hui Ethnic Township (乌什塔拉回族乡)
Ili Kazakh Autonomous Prefecture (伊犁哈萨克自治州)
Khorgas City (霍尔果斯市)
---- Iqegaxan Xibe Ethnic Township (伊车嘎善锡伯族乡)
Yining County (伊宁县)
---- Yuqunweng Hui Ethnic Township (愉群翁回族乡)
Huocheng County (霍城县)
---- Sangong Hui Ethnic Township (三宫回族乡)
Zhaosu County (昭苏县)
---- Qagan Us Mongol Ethnic Township (察汗乌苏蒙古族乡)
---- Xat Kirghiz Ethnic Township (夏特柯尔克孜族乡)
---- Hosumtuharson Mongol Ethnic Township (胡松图喀尔逊蒙古族乡)
Tekes County (特克斯县)
---- Hujirti Mongol Ethnic Township (呼吉尔特蒙古族乡)
---- Kokterak Kirghiz Ethnic Township (阔克铁热克柯尔克孜族乡)
Nilka County (尼勒克县)
---- Hoh Hothor Mongol Ethnic Township (科克浩特浩尔蒙古族乡)
Tacheng Prefecture (塔城地区)
Tacheng City
---- Axili Daur Ethnic Township (阿西尔达斡尔族乡)
Usu City (乌苏市)
---- Jirgiltigolin Mongol Ethnic Township (吉尔格勒特郭愣蒙古族乡)
---- Tablihat Mongol Ethnic Township (塔布勒合特蒙古族乡)
Emin County (额敏县)
---- Emalgolin Mongol Ethnic Township (额玛勒郭楞蒙古族乡)
---- Hujirti Mongol Ethnic Township (霍吉尔特蒙古族乡)
Guangxi Zhuang Autonomous Region (广西壮族自治区) (6)
Liuzhou City (柳州市)
Rongshui Miao Autonomous County (融水苗族自治县)
---- Tonglian Yao Ethnic Township (同练瑶族乡)
---- Gunbei Dong Ethnic Township (滚贝侗族乡)
Sanjiang Dong Autonomous County (三江侗族自治县)
---- Tongle Miao Ethnic Township (同乐苗族乡)
---- Gaoji Miao Ethnic Township (高基苗族乡)
---- Fulu Yao Ethnic Township (富禄瑶族乡)
Sichuan Province (四川省) (5)
Liangshan Yi Autonomous Prefecture (凉山彝族自治州)
Muli Tibetan Autonomous County (木里藏族自治县)
---- Eya Nakhi Ethnic Township (俄亚纳西族乡)
---- Wujiao Mongol Ethnic Township (屋脚蒙古族乡)
---- Baidiao Miao Ethnic Township (白碉苗族乡)
---- Xiangjiao Mongol Ethnic Township (项脚蒙古族乡)
---- Guzeng Miao Ethnic Township (固增苗族乡)
Inner Mongolia Autonomous Region (内蒙古自治区) (3)
Hulunbuir City (呼伦贝尔市)
Ewenki Autonomous Banner (鄂温克族自治旗)
---- Bayan Tal Daur Ethnic Township (巴彦塔拉达斡尔族乡)
Morin Dawa Daur Autonomous Banner (莫力达瓦达斡尔族自治旗)
---- Bayan Ewenki Ethnic Township (巴彦鄂温克族乡)
---- Dulari Ewenki Ethnic Township (杜拉尔鄂温克族乡)
Yunnan Province (云南省) (2)
Honghe Hani and Yi Autonomous Prefecture (红河哈尼族彝族自治州)
Hekou Yao Autonomous County (河口瑶族自治县)
---- Qiaotou Miao and Zhuang Ethnic Township (桥头苗族壮族乡)
Jinping Miao, Yao, and Dai Autonomous County (金平苗族瑶族傣族自治县)
---- Zhemi Lahu Ethnic Township (者米拉祜族乡)
Qinghai Province (青海省) (1)
Haibei Tibetan Autonomous Prefecture (海北藏族自治州)
Menyuan Hui Autonomous County (门源回族自治县)
---- Huangcheng Mongol Ethnic Township (皇城蒙古族乡)