How about using a ee.Join to do a join?

var point = ee.Geometry.Point([-94.73665965557193, 35.915990354302]);

print('Point Geometry:', point);
var startDate = ee.Date('2016-01-01');
var endDate = ee.Date('2016-12-31');

  
var lstDataset = ee.ImageCollection('OREGONSTATE/PRISM/AN81d')
                  .select('tmean')
                  .filterDate(startDate, endDate)
                  .filterBounds(point)
                  .map(function(image) { return image.clip(point); });
print("lstDataset", lstDataset)    

var NTTempdataset = ee.ImageCollection('NASA/VIIRS/002/VNP21A1N')
    .select("LST_1KM") // Select the LST_1KM band
    .filterDate(startDate, endDate) // Filter by date
    .filterBounds(point) // Filter by region
    .map(function(image) {
        return image
            .clip(point) // Clip to the region
            .rename("LST_1KM_Night"); // Rename the band to LST_1KM_Night
    });
print("NTTempdataset", NTTempdataset)      

var joined = ee.Join.saveBest({
  matchKey: 'other',
  measureKey: 'garbage',
  outer: true
}).apply({
  primary: lstDataset, 
  secondary: NTTempdataset, 
  condition: ee.Filter.maxDifference({
    difference: 100000000,
    leftField: 'system:time_start', 
    rightField: 'system:time_start'})
})

// Do something to these:
var withMatches = joined.filter(ee.Filter.neq('other', null))
print(withMatches.size())
// Do something else to these:
var withoutMatches = joined.filter(ee.Filter.eq('other', null))
print(withoutMatches.size())