Let’s look at important things here –
Sun - Sun represents Personality, King, Government, Father, Authority, Career, Top Positions, Ego, Self Esteem, Health, Education etc.
Swati - Swati is nakshatra of independence, Justice, Fair-Play and Business People. For more information on Swati Nakshatra, please check this link - https://www.astrosaxena.com/swanaksh.
Libra - As Swati is a part of Libra, Libra sign and its representations also become important. Libra is the 7th sign of Zodiac Belt, hence it represents the energy and things related with 7th house of horoscope, i.e. Market Place, Business, Partnerships, Relations etc. Libra is sign of Balance, i.e. striking the Balance between 2 parties/ideologies or even at personal level between our own dilemmas. It is sign of Peace and Diplomacy. And this is what we are seriously looking for after the conflicts and disagreements of Virgo, i.e. Peace to prevail. At personal level, Libra is seen as sign of Relationships. Libra is consisted of 2 and half Nakshatra named Chitra, Swati and Vishakha. Libra's lord is Venus only.
Rahu - As Rahu rules Swati, Rahu's position and dignity is important to know about the overall functioning of any planet in Swati.
Venus - As Venus rules Libra, Venus position and dignity is important to know about the overall functioning of any planet in Swati.
Houses Involved – Also, we can’t afford to forget the houses involved as a planet can be ruling different houses and sitting in different house for every person as per ascendant and planet’s position. To know overall affect, we have to consider the houses involved as those areas of life are being impacted.
Interpretation of Sun in Swati Nakshatra – This is where Sun gets debilitated. One of the reason can be that Swati is ruled by Rahu and Rahu/Ketu eclipses the Sun. Hence, Sun is debilitated in Rahu's nakshatra. Another reason can be that Libra is sign of relationship and Sun is Ego. So, if you want to maintain a relationship, you have to let go of your ego. Last reason can be that Swati is in middle of Libra sign. It is natural 7th sign which represents the things or energies of 7th house. 7th house represents evening time when Sun sets. As Sun sets in 7th house,it is considered weak in 7th sign Libra, especially in middle portion of Libra where Swati Falls. Now, as Sun represents Career, Authority & Recognition and Sun is weak in Swati then it doesn't mean that a person with Sun in Swati will never have any career, authority or recognition. It only means that he has to create his own career, authority or recognition. It means he may not get any support from people in authorities and become authority in himself through his own business. As Swati and Libra both represent business, these people shine in their own business. Sooner of later they have to get into their own work. Relationship with Father also may not be great one as Sun represents Father and it is weak. They can be good Mediator, Counselors, Diplomats, Lawyers or Judges. They can be very fair in dealing. As usually, their can be ego conflicts in relationship. It is better for these people to make a goal from very beginning that they need to do their own business as job setup may never bring them good,
Role of Rahu – Rahu placement is important to guide Sun in right direction, being Swati's lord.
Role of Venus - Likewise, Venus placement is important to guide Sun in right direction, being Libra lord.
Other Factors – And of course, we need to consider conjunction, aspects, house lordship, house position and dashas etc to know the exact results of Sun in Swati. So, we always need to take a holistic view of chart rather than just 1 planetary position.
Conclusion – So, this is how I see Sun in Swati can work in a chart.
Hope this helps. Please post any comment or query you may have.