Output Current of NodeMCU Digital Pin
Espressif says that the ESP8266 (that's likely in your NodeMCU) can deliver 12mA per digital pin with a total of 72mA across all pins.

That answers your question but I don't think it'll solve your problem.  The datasheet for the DS18b20 says it draws maybe 6mA tops so you should not be running into current limits.

Using your description I don't understand quite what your circuit looks like.  Perhaps you could add a circuit diagram.