Sri Chaitanya Mahaprabhu passed through Varanasi twice during the years He travelled after accepting sannyasa. On both occasions He was found at Chandrasekhara Acharya's house.
A Brief Meeting on the Way to Vrindavana #
The first contact came in passing. As Sri Chaitanya Mahaprabhu journeyed toward Vrindavana, He stopped in Varanasi only briefly. Chaitanya-charitamrita records that Tapana Mishra's entire family took the remnants of the Lord's food that day, and that "when news spread that the Lord had come, Candrasekhara came" to see Him. It is a single verse, no more - a courtesy call rather than a stay - but it establishes that Chandrasekhara Acharya was already known to Sri Chaitanya Mahaprabhu well before the Lord's longer visit on His way back.

Two Months Under One Roof #
That longer visit came after Sri Chaitanya Mahaprabhu had seen Vrindavana and turned back toward Jagannatha Puri. The text says that Chandrasekhara Acharya had already seen the Lord's arrival in a dream the night before. He rose in the morning and went outside the city to receive Him in person. He then took Sri Chaitanya Mahaprabhu into his own home. That same day he also invited Balabhadra Bhattacharya, the brahmana companion who had escorted the Lord on His journey, to take lunch there. For the full two months that followed, Sri Chaitanya Mahaprabhu lived at Chandrasekhara Acharya's house and accepted His daily meals at Tapana Mishra's residence nearby. Krishnadasa Kaviraja Goswami records this arrangement in a single couplet. It names Chandrasekhara Acharya, Tapana Mishra and Tapana Mishra's son Raghunatha Bhattacharya as "the prominent devotees at Varanasi." It is one of the plainest and simplest facts in the whole of Sri Chaitanya-charitamrita. It is also the clearest evidence of how much Sri Chaitanya Mahaprabhu trusted this one household.
Witnessing the Lord's Victory in Kashi #
During this same stay, Sri Chaitanya Mahaprabhu performed one of His most important public acts in Varanasi. He debated with the Mayavadi sannyasis of the city, led by the famous scholar Prakashananda Sarasvati. After that, at the temple of Bindu Madhava, He explained Srimad-Bhagavatam as the true commentary on Vedanta-sutra. Chaitanya-charitamrita's own summary of this episode says that a Maharashtrian brahmana devotee arranged the sannyasis' meeting with the Lord. It was not Chandrasekhara Acharya. This difference matters, because later retellings sometimes confuse who called that famous gathering. Chandrasekhara Acharya's part was smaller but still notable. A shorter retelling of the episode records that "Chandrasekhara, Tapana Mishra and Sanatana" were all "extremely pleased" on hearing the arguments and seeing Sri Chaitanya Mahaprabhu's victory. The explanation that goes with it notes that the Lord's only local friendships in Varanasi were with Chandrasekhara Acharya and Tapana Mishra. This was so even as His fame in the city spread far beyond His own small circle after that victory. In other words, from this same household Sri Chaitanya Mahaprabhu quietly began to turn the whole city's leading Vedanta scholars to devotion, without ever moving from this house.
Chandrasekhara Acharya welcomed Balabhadra Bhattacharya, a brahmana, to lunch that first day. Balabhadra was the traveling companion who had cooked for Sri Chaitanya Mahaprabhu and looked after Him throughout the hard journey to and from Vrindavana. His presence at Chandrasekhara Acharya's table is a small sign of how completely the household had opened itself to the Lord's entire traveling party, not to Mahaprabhu alone.
By the time Sri Chaitanya Mahaprabhu finally left Kashi for Jagannatha Puri, He had spent two full months as a guest under Chandrasekhara Acharya's roof. He had converted the city's most prominent Mayavadi sannyasis to devotional service. And at that same front door He had received one of the Six Goswamis of Vrindavana, as told in Relationship to Sanatana and Rupa Goswami.

